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Speed kills.

As coaches, we have often heard and used this phrase—and for good reason. Speed is a critical factor in team sports: whether it’s outrunning angles on a football field, winning a 50-50 ball on the soccer pitch, or recovering possession in basketball, speed consistently proves to be a decisive advantage. Many coaches preach the value of speed, and athletes strive to improve it. The fundamental approach to speed training seems straightforward: run fast and do it often. Many athletes and coaches encounter a common roadblock, however—progress stagnates and the expected speed improvements plateau.

At this juncture, coaches can be temped to turn to various adjustments. Should we add more volume? More intensity? Or should we shift focus entirely? The answer, I believe, is rooted in a fundamental principle: precise, intentional, and consistent speed development must be the unwavering priority.

Sports are won and lost with speed—I’m in my 11th year of coaching (working primarily with college and high school athletes), and I have yet to see a slow and sluggish athlete thrive. Speed can provide a distinct advantage in team sports, especially at the high school level. Here at Madison-Ridgeland Academy (MRA), we are blessed with great kids who have a tremendous work ethic and are highly competitive, almost to a fault sometimes. What we are not blessed with—especially on the football field—is size. We are often outmatched physically. So, the question I had to ask myself was “How can we provide an X-Factor for our athletes?” And, I landed on making our system a speed-based program.

When programming for any of our teams, male or female, speed is in the forethought of my process. Does this make us faster? If the answer is “No,” I figure out a better way. Does that mean we neglect strength? Simply put, “No.” Strength is a pillar of our program—but the frame that we operate out of is that strength training is aiding us in our speed development.

When programming for any of our teams, male or female, speed is in the forethought of my process. Does this make us faster? If the answer is “No,” I figure out a better way, says @Coach_GAdams. Share on X

Breaking the Cycle of Inconsistency

Despite the desire for faster and more explosive athletes, many coaches fail to treat speed as the core focus of their training regimen. Speed work is often neglected during the in-season phase or undermined during the off-season by the overuse of long, slow conditioning drills that do little to nurture explosiveness.

If we are serious about improving speed, we need to break the cycle of inconsistency.

The first hurdle is making speed the cornerstone of our training philosophy. We need to approach every aspect of preparation—from practices to conditioning—through the lens of speed development. This requires a shift in mindset for most coaches. Speed must be ingrained as a core identity of the entire program, rather than treated as a temporary priority or an afterthought. Establishing this unwavering focus is essential for achieving transformative results.

Despite wanting faster & more explosive athletes, many coaches fail to treat speed as their core training focus. Speed work is often neglected in-season or undermined in the off-season by the overuse of long, slow conditioning. Share on X

Once we have made this paradigm shift, now we start chasing performance. When we can focus on the right things, speed improvements can come quickly. The puzzle, however, gets harder when those improvements start to plateau. Where do we go from here? How do we get the speed numbers to start improving again?

One of the most common pitfalls in speed training is the tendency to focus on volume rather than quality. When I first started, I believed that if we sprinted more often and worked harder, we would outlast the other team. However, when I evaluated the intent behind the work, I realized these “sprints” were often performed with submaximal effort, essentially turning them into fast jogs. By definition, that isn’t true sprinting—instead of gaining the speed advantage we were striving for, we were actually achieving the opposite.

This realization led me to reevaluate how we were programming our speed training. The belief that more is better often leads athletes and coaches to increase the number of sprints or conditioning drills, assuming that more repetitions will automatically lead to faster performance. However, speed is a skill that thrives on intensity and precision, not sheer volume. The misunderstanding here is rooted in the idea that endurance and speed can be trained the same way—but in reality, they require very different approaches.

In contrast to volume-based training, speed development thrives on short, high-quality efforts. To truly enhance speed, an athlete needs to perform sprints at maximum velocity, with full effort, and with complete recovery between each repetition. This ensures that each sprint is of the highest possible quality and trains the body to operate at peak efficiency. Speed training heavily taxes the central nervous system because it involves maximal or near-maximal efforts.

To truly enhance speed, an athlete needs to perform sprints at maximum velocity, with full effort, and with complete recovery between each repetition, says @Coach_GAdams. Share on X

Unlike aerobic or endurance work, where fatigue builds gradually, speed training requires immediate and explosive outputs, which engage fast-twitch muscle fibers and heavily stress the nervous system. These maximal outputs demand significant energy and create a high level of neuromuscular fatigue, which takes time to repair. Inadequate recovery can lead to chronic fatigue, slower sprint times, and the inability to maintain proper technique during high-speed efforts. Over time, this creates a vicious cycle where athletes are no longer training at their peak, reinforcing poor movement patterns and limiting overall speed potential.

Maximal effort speed training is essential for developing explosive sprint ability on the field, such as chasing down a ball, breaking away from defenders, or closing space on an opponent. These efforts typically last 5 to 10 seconds and require rest periods at a 1:10 to 1:20 ratio to maximize recovery and ensure high effort performance. For example, after a 10-second sprint, the athlete would rest for a minimum 100 to 200 seconds. This allows them to maintain proper sprint mechanics and exert maximal effort on each repetition, which is crucial for enhancing pure speed and game-changing explosiveness.

Speed is not just about raw athleticism; it’s about proper mechanics that ensure every ounce of energy is used effectively. Developing good sprint mechanics is crucial because the slightest inefficiency can cost valuable time and energy, especially when an athlete is fatigued.

Resisted Sprints & Best Practices with High School Athletes

Another solution I use to break through these plateaus is implementing various types of resisted sprinting. Resisted sprints are a highly effective tool for improving speed, acceleration, and power. These methods are often used to enhance an athlete’s ability to generate force, improve sprint mechanics, and develop explosiveness—all of which are critical components of speed. Resisted sprints involve adding external resistance, such as a sled, prowler, or band, to the athlete’s sprint.

The primary benefit of resisted sprints is the improvement in an athlete’s ability to generate force. When an athlete sprints with resistance, such as pulling a sled, their muscles must work harder to overcome the additional load. This increased demand trains the neuromuscular system to apply greater force during the sprint, particularly during the acceleration phase. The increased force production translates directly to unweighted sprints, where the athlete will be able to push harder and generate more power off the ground. In sprinting, force application is everything. The faster and harder an athlete can push off the ground, the faster they will accelerate. Resisted sprints strengthen the key muscles involved in sprinting, such as the glutes, hamstrings, and quads, making it easier to reach top speed faster.

In sprinting, force application is everything. The faster and harder an athlete can push off the ground, the faster they will accelerate, says @Coach_GAdams. Share on X

Resisted sprints are particularly effective for improving the acceleration phase of sprinting, which covers the first 10-30 yards. This phase requires the athlete to lean forward and generate significant horizontal force to build speed from a stationary or slow-moving position. Resisted sprint training forces the athlete to maintain an aggressive forward lean while driving their legs with more intensity to overcome resistance. In team sports, the ability to accelerate quickly can make the difference between getting to the ball first, making a defensive play, or winning a race. Athletes who improve their acceleration can close gaps faster, react quicker, and gain a competitive edge.

Resisted sprints also serve as a valuable tool for refining sprint mechanics, especially during acceleration. With resistance, athletes must focus on driving their knees forward, maintaining proper body angles, and extending their hips for maximal power. The added resistance forces athletes to stay in the proper acceleration posture longer, helping them reinforce good technique. Good sprint mechanics are crucial for reducing wasted energy and improving running efficiency. Resisted sprints force athletes to focus on their form while under pressure, which helps transfer these mechanics into regular, unweighted sprints. Athletes who maintain proper form are more likely to avoid injuries and improve their top-end speed.

Best Practices for Resisted Sprints

1. Gradual Progression: Start with light-to-moderate resistance and gradually increase the load as the athlete’s strength and mechanics improve. Too much resistance too soon can alter running mechanics and reduce the effectiveness of the drill.
2. Focus on Form: The goal is to enhance sprint mechanics, so athletes must maintain proper form while sprinting with resistance. Excessive resistance that causes athletes to “grind” through each step will do more harm than good. Athletes should still be sprinting, not struggling through the movement.
3. Monitor Distances: Resisted sprints are most effective for short distances, particularly the acceleration phase (10-30 yards). Sprinting with resistance over longer distances can lead to form breakdowns and inefficient movement patterns.
4. Incorporate Unresisted Sprints: Always pair resisted sprints with unresisted sprints in the same session. This helps athletes transfer the strength and power gains from the resisted sprints into regular sprinting form, enhancing overall speed development.

Always pair resisted sprints with unresisted sprints in the same session. This helps athletes transfer the strength and power gains from the resisted sprints into regular sprinting form, enhancing overall speed development. Share on X

The Importance of Timing & Tracking

Lastly, you have to track the data. I don’t care what implements you are using (timing gates, GPS, video analysis, stopwatch, etc.), but the numbers have to be monitored consistently. One of the most important tools and insights we have is the ability to track sprint times. Monitoring sprint times throughout the year provides invaluable insights into an athlete’s performance and progression. By consistently measuring sprint times, coaches and athletes can monitor speed development, identify trends, and address weaknesses that may be holding back overall performance.  

I focus on a few key metrics across all sports to optimize performance. Each week, we test a Fly 10 using both a 5-yard and a 20-yard lead-in. These times help us calculate a rolling average to monitor performance trends and provide athletes with regular opportunities to reset their personal bests. Ideally, athletes should match or surpass their personal bests at least once every four weeks.

Video 1. Running timed sprints.

Tracking these metrics serves two purposes: it encourages athletes to consistently strive for high performance and facilitates important conversations when times begin to decline. For instance, if an athlete’s performance drops, it can signal the need to address readiness, recovery, or potential injuries.

In addition to the Fly 10, we use GPS tracking to measure maximum speeds (MPH) in field sports, providing valuable insights into practice and game demands. Combining the Fly 10 data with GPS metrics allows us to align training with the physical demands of competition. We ensure athletes regularly reach max velocities during the week to condition their tissues and prepare them for the high-speed demands they may face in games. Together, these tools help us train effectively and ensure our athletes are ready to perform at their best on game day.

In team sports, where speed can be the deciding factor in key moments, regularly tracking sprint performance offers several crucial benefits. Tracking sprint times allows you to gauge an athlete’s speed development over time. By comparing sprint times from the start of the season to mid-season and the off-season, I can see whether the training program is yielding the intended results or if adjustments are needed.

Progress is not always linear. Speed training is different from strength training. It is not linear and can’t be. There are many variables and factors that play a role in good speed training sessions, MPH readings, or timed sprints. It is not as simple as “add a 5.” If that was the case, there would be no need for this article, we would all just preach “run faster than you did last week.” Sprint times provide objective data that shows whether an athlete is getting faster or if their performance is stagnating. This allows us to adjust the training focus—whether adding more intensity, focusing on mechanics, or addressing recovery needs.

By comparing sprint times from the start of the season to mid-season and the off-season, I can see whether the training program is yielding the intended results or if adjustments are needed, says @Coach_GAdams Share on X

Another benefit of tracking sprint times is that they can be a reliable indicator of an athlete’s freshness or fatigue levels. A sudden decline in sprint performance could signal overtraining, excessive volume, or inadequate recovery. By tracking times, you can spot early signs of fatigue that might lead to burnout or injury if left unchecked. In team sports, where players often face demanding schedules, knowing when an athlete’s speed is declining can prevent injuries. If I’m noticing a drop in sprint times over several weeks, it may be time to taper the athlete’s workload, adjust recovery protocols, or focus more on speed maintenance rather than volume-heavy conditioning.

Tracking sprint times over various distances is a powerful tool for breaking speed plateaus by identifying specific weak points in an athlete’s sprinting ability. For example, an athlete may excel in the acceleration phase (0-10 yards) but struggle to maintain top-end speed (20-40 yards). These insights allow you to break down the sprinting process and profile athletes based on their individual needs.

In team sports like soccer and football, the demands for sprinting vary—whether it’s quick bursts off the line, sustained sprints down the field, or rapid deceleration. By analyzing split times at different distances, you can pinpoint where an athlete is hitting a plateau and target specific aspects of their sprinting. Whether it’s refining acceleration mechanics, improving speed endurance, or enhancing change of direction, addressing these weak points with focused training allows athletes to break through performance barriers.

This targeted approach not only optimizes an athlete’s sprinting ability but ensures that training is aligned with the unique demands of their sport, leading to more comprehensive and sustained speed development.

Using speed training metrics like Fly 10 times to inform strength training involves identifying specific performance deficiencies—such as maximal velocity, acceleration, or force production—and tailoring programming to address them. For velocity-deficient athletes, who excel in short bursts but struggle to maintain or improve top-end speed, the focus should be on explosive and plyometric exercises (e.g., bounding, skips, or barbell jump squats), Olympic lift derivatives, and sprint-specific work with minimal emphasis on heavy, slow lifts. Force-deficient athletes, who lack power in acceleration or low-velocity movements, benefit from foundational strength exercises (e.g., squats, deadlifts), power-based movements like trap-bar jumps and heavy sled sprints, and plyometric drills such as depth or loaded jumps.

By analyzing metrics such as flying sprint times, split data trends, and force-velocity profiles, you can determine whether an athlete’s deficiency lies in velocity or force production. Adjusting the strength program accordingly ensures targeted improvements—velocity-deficient athletes emphasize rate of force development (RFD) and elasticity, while force-deficient athletes focus on building strength and applying force effectively. Resisted and assisted sprint variations complement both profiles, enhancing specific adaptations for speed and power development.

Another factor that is difficult to quantify—but is invaluable—is creating competition. Consistently tracking sprint times can be a great motivator for athletes. Knowing that their progress is being measured fosters a competitive environment, both within the team and for personal goals. Athletes can compare their current times to past performances or to teammates, fueling a drive to improve.

Furthermore, posting sprint times publicly or using leaderboards can foster team camaraderie and push athletes to strive for faster times, knowing they are being measured and compared in a way that reflects directly on game-day performance.

One of the key benefits of tracking sprint times is that it allows you to evaluate the effectiveness of specific training interventions. If you introduce a new speed training drill, implement resisted sprints, or adjust conditioning volumes, tracking sprint times can reveal whether these changes are having the desired effect. Objective feedback from sprint times helps you determine which training methods are working and which aren’t. If a new technique or program leads to better sprint times, you know you’re on the right track. Conversely, if sprint times stagnate or decline after introducing a certain drill or conditioning block, you can quickly adjust the program before it negatively impacts performance.

For example, if you implement resisted sprints to improve acceleration but don’t see faster 20-30 yards times after a few weeks, you might need to adjust the resistance load or revisit sprint mechanics drills to address the underlying issue. Sprint times offer real-time feedback to guide these decisions.

Where We’ve Been and Where We’re Going

Over the years, I’ve witnessed the transformative power of a speed-first approach in athlete development. Speed is the great equalizer in sports—regardless of size or strength, the ability to accelerate, maintain top-end velocity, and change direction quickly can define success. Watching athletes consistently set personal records and shave time off their Fly 10s throughout the season has been one of the most rewarding aspects of my coaching journey. These improvements are not just numbers on a stopwatch; they represent hours of hard work, focus, and the willingness to embrace a process rooted in precision and intentionality.

More importantly, these gains have a ripple effect on the athletes’ mindset. As their speed improves, so does their confidence and competitiveness. It’s one thing to tell an athlete they’re getting faster, but when they feel it—when they start beating their opponents to the ball, breaking away from defenders, or recovering to make game-changing plays—it changes the way they approach not just their sport, but their development as a whole. They become more engaged, more determined, and more willing to push their limits. For me as a coach, these moments are what make the process so fulfilling. Speed is more than a metric—it’s a catalyst for growth, both on and off the field.

Speed is more than a metric—it’s a catalyst for growth, both on and off the field, says @Coach_GAdams Share on X

O­­­­­ne moment that stands out is when a player who initially struggled with acceleration managed to cut nearly two-tenths of a second off their Fly 10 time after targeted interventions. It wasn’t just the time improvement that impressed me—it was the athlete’s newfound belief in their ability to compete and excel. These moments reaffirm the importance of addressing individual needs and tailoring our methods to maximize every athlete’s potential.

Building on this success, we’re developing a comprehensive system to profile athletes based on their specific deficiencies. Whether it’s insufficient force production, a lack of explosive acceleration, or difficulty sustaining top-end speed, this profiling system will enable us to design precise, individualized training plans. By integrating advanced tools like force-velocity profiling and GPS tracking, we’re gaining a deeper understanding of each athlete’s unique strengths and areas for growth.

This personalized approach does more than improve PRs or sprint times—it fosters a culture of accountability, growth, and excellence. Athletes aren’t just running faster; they’re learning to push their limits, embrace challenges, and set higher goals. As a coach, there’s nothing more fulfilling than seeing these lessons extend beyond the field, shaping their mindset for success in all aspects of life.

Looking ahead, our focus is clear: refine the profiling system, continue leveraging data to guide our training, and ensure that every athlete feels empowered to break through barriers. By staying committed to innovation and athlete-centered coaching, we’re not just building faster athletes—we’re building resilient, driven individuals ready to excel in competition and beyond.

Since you’re here…
…we have a small favor to ask. More people are reading SimpliFaster than ever, and each week we bring you compelling content from coaches, sport scientists, and physiotherapists who are devoted to building better athletes. Please take a moment to share the articles on social media, engage the authors with questions and comments below, and link to articles when appropriate if you have a blog or participate on forums of related topics. — SF

I am about to retire from teaching, which has a way of forcing you to look back on your career—which, for me, has included 35 years of coaching. As I reflect, I have been passionate in my pursuit of developing speed. As I reflect, I also wonder if I have the led the life of Captain Ahab in a self-destructive search for his white whale or that of Arthurian legend Perceval in his quest for the Holy Grail to save Camelot. My quest has taken me down many paths—some destructive, some enlightening.

Regardless of where I was on the journey—which still continues—I’ve always dealt with some form of strength and the kinds of strength that have been defined. We all know and love max strength. We can thank Supertraining and other Cold War-era literature for concepts like Speed Strength and Strength Speed, which really just define how fast a bar is moving in a weight room scenario. We can ask football coaches about Farmer Strength, which I guess is the ability to be explosive throwing things. I think I possess Old Man Strength which is the ability of an old guy to tap into his “muscle memory” and perform a feat of strength that wows younger people (the long-range result is the old guy then needs three visits to the chiropractor, but feels good emotionally that he still “has it”).

While all of those things are real and legitimate, I have always been searching for attributes that someone fast has and slow people don’t have: something I am calling Sprint Strength.

I have always been searching for attributes that someone fast HAS and slow people DON’T HAVE: something I am calling *Sprint Strength*, says @korfist. Share on X

One definition would be how fast you can be strong? Another might be how fast can you apply force into the ground? But it can also mean how does your body react with a large amount of force running through your body? What gets absorbed, what gets reused, what creates displacement of joints, and what turns to heat? That force can be what happens when your foot hits the ground, but it can also mean how it reacts to a limb that constantly stops, accelerates, and decelerates at a high velocity. My lifelong goal has been to find the Holy Grail strength that can turn 11.5 athletes into 10.3 speed demons. My white whale is Sprint Strength.

My Ahab moments would be a chronology of equipment acquisitions, most of which have ended up like the whale carcasses left behind The Pequod. The tools that have helped tremendously have been 1080 Motion equipment—not only in their training applications, but in the data I can mine from applying it. In addition to isolating specific movements that are vital to speed—like plantar flexion torque—I can also put higher amounts of force into a movement to see how the body will react. An example might include a leg getting pulled into flexion and the body responds with spinal flexion, either to lower the center of mass to not fall or use the spine to dissipate forces. Both initial reactions are neural in that safety and balance precede performance in every movement. Or, in more of a subjective assessment, athletes can feel other muscles jumping to help absorb the force, creating a muscular compensation pattern.

Fatigue can have the same impact. When performing an exercise forcing plantar flexion torque, after a few reps athletes with weak plantar flexion will note that they feel their hamstring start to fatigue. That is an indication that their plantar flexors lack endurance or strength to keep the movement going. Since the athlete has a rep target, their body resigns to help reach the target (more on plantar flexion later).

With access to weight room numbers, 1080 Sprint data, 1080 Synchro data, and video, I have started compiling various numbers and exercises that have carryover to sprinting fast. I think what surprised me the most was that it wasn’t about the highest maxes and big weight room numbers, but it was about thresholds—or, just the concept of being strong enough to go past the threshold or “speed barrier.” And once over that barrier, it will be enough to set up the next step. Speed is like a perfect story: one good step sets up another, until it doesn’t. And then we see how the body will solve the problem. So “call me Ishmael” and let’s see how this story unfolds.

Speed is like a perfect story: one good step sets up another, until it doesn’t. And then we see how the body will solve the problem, says @korfist. Share on X

Ahab Meets Inception: The Swing Leg

The story I have to tell here is not something I’m going to lay out in a chronological narrative. I want to be trendy and jump around to different moments of a sprint, ranging from a period of time in the cycle of the leg, to a different distance on the track, or even variables such as not running straight but curved. I promise I am not trying to be a fancy Christopher Nolan/ Quentin Tarantino type of writer—I am just collecting my thoughts as I prepare for my track season. To start this series, I want to look at the most important, undertrained aspect of running: the swing leg.

Research in the last 10 years has changed how we see sprinting. As we move further away from the 1980’s research that said the stronger the athlete, the faster the athlete, we start to look at other factors…because the strongest guy isn’t always the fastest. But since we have focused so much on strength, or Ground Reaction Force, we have forgotten the other vital aspect to all phases of a sprint… limb velocity.

Ken Clark’s multiple research papers on limb velocity were the first times I came across it mentioned in research. When I started my deep dive, I discovered Chinese researchers have recognized the importance of limb velocity as far back as 2014, with Y. Sun’s paper “How Joint Torques Affect Hamstring Injury Risk in Sprinting Swing-Stance Transition” followed by Y. Zhong’s paper “Joint Torque and Mechanical Power of Lower Extremity and Its Relevance to Hamstring Strain During Sprint Running.” The latter paper emphasizes an equation that makes the most sense to me in determining speed.

NET= MUS+GRA+EXF+MDT

• NET is the sum torque acting on a joint. Torque is what gives an athlete the power to pull their body forward 60 degrees from touchdown.
• MUS is power generated by muscle contractions.
• GRA is gravitational forces acting at the center of mass.
• EXF is generated at joints by GRF acting on the foot.
• MDT is the mechanical interactions occurring between limb segments and is the sum of all interaction torques produced by segment movements, such as the angular velocity and angular acceleration of segments.

Muscle power is agonist and antagonist muscles, multiplied by the angular velocity of the joint.

Both of these equations make more sense to me to determine running speed. We have relied on just vertical force for too long—mainly because it’s something we can measure in the weight room. These equations, instead, account for the athlete who can’t squat twice his body weight but can still run. They can also account for the athlete who can squat the house but can’t run. Maybe his limbs have become too heavy to move fast enough to run fast? Or their body weight has surpassed the threshold of what of what it can absorb and hold up? We can use this formula to describe a variety of athletes.

But in this article, we are looking at limb speed. Ken Clark showed in a brilliant YouTube and research paper that when our foot hits the ground, it has to pull our mass over a 60-degree range of motion. To pull your body over that range as quickly as possible, your hip has to create torque. Torque is a rotational element. Think of your body as a socket. Your foot is the actual socket and your leg is the lever that pulls it forward. The socket can go 360 degrees around—but we are stuck in a 60-degree range. We can create more torque by having a longer lever, which we can do to some extent by having a straighter leg on contact or by pushing the lever faster. In a real sense, that would mean bringing the leg faster down to the ground.

How do we train this?

A simple exercise is just a leg swing, but not like the one I see most teams warming up with. Our hip has to rotate or swing 60 degrees. When I see athletes swinging their leg, their torso rotates back and forth, so the range of motion is about half. I have my athletes support their torso by putting their hands on something fixed and focus on not moving their torso. And instead of swing for fun, have them swing with the intent of going as fast as possible. Because the power really comes in the reversal of the leg.

Video 1. Leg Swings.

But swinging a straight leg is not what happens when we run. Upon toe-off, we fold our lever (bend our knee) to reduce the drag (slow down) on our angular velocity (swing leg speed). We can train that too. Toe-off is the moment the foot comes off the ground at the end of the 60-degree range. Some of the speed of the toe-off comes from the energy created by the tension of the foot on the ground. More will come from a clean toe-off, meaning the ability of the foot to finish its rotation with the heel moving forward, not off to the side (see below).

From there, quite a bit of hip flexor activity brings the leg through. It starts with the iliopsoas complex and rectus femoris then takes over, reaching peak force when the swing leg knee is slightly in front of the stance leg. From that point, limb speed has to be reduced by 78% to prepare for the reversal of the limb, asking all the hamstrings to put on the breaks. This is why we try to find eccentric hamstring exercises to prevent strains, which occur at this point of the sprint cycle.

This concept may explain why high knee drills may not be helping your athlete get faster: the peak power, force, and velocity is at midpoint of the swing leg knee passing the stance knee. High knee, hip flexor drills accelerate vertically in an area where the limb is decelerating and reversing course in a sprint gait cycle.

Gaku Kakehata of the University of Tokyo has three great papers looking at this part of the running cycle. He creates two points in the gait cycle: a switch and a scissor.

1. A switch has a Part A and a Part B. Part A would be the high knee action and Part B would be the toe-off to knees passing each other.
2. A scissor is the relationship between the two legs.

Research showed that the Switch B is correlated with stride frequency. So, what can we do to get that leg to pull the toe off the ground and pull the thigh through faster? We can tap into reflexes. A stumble reflex is what prevents us from tripping. If the brain senses the foot is stuck, it will fire extra hard to get the foot down in time to prevent a trip or fall. We can access this quality in a couple ways. Simply, we can tap our foot into the ground and bring the knee forward as quickly as possible.

A stumble reflex is what prevents us from tripping. If the brain senses the foot is stuck, it will fire extra hard to get the foot down in time to prevent a trip or fall. We can access this quality in a couple ways, says @korfist. Share on X

Video 2. Tap and Go.

Or, we can take inspiration from Ayako Higashihara’s paper “Differences in the Recruitment Properties of the cortispinal pathway between the biceps femoris and rectus femoris muscles”—his research shows how the rectus femoris can “produce rapid increase in motor units” (or, have to turn on a lot faster to prevent a trip of fall). So, we need something to turn everything on faster. This coincides with Kakehata’s work showing that the faster the rec fem fires, the better the scenario for a good scissors and switch. Again, we can tap into a stumble reflex by putting our foot in an ankle cuff attached to a weight stack and let your leg go back 20 degrees. Give a little pull forward to create momentum in the stack, and let it drop for a moment to give the feeling of a trip, and then pull forward hard. In fancy terms, it is an oscillatory isometric for hip flexors.

Video 3. Slack and go.

Looking at how one limb functions by itself would be intralimb dynamics; or, in Kakehara’s paper, the rec fem and bicep femoris contract and reflex inside one limb. Looking at the relationship between the two limbs would be interlimb dynamics, or a scissor. Interlimb dynamics are what is required for us to move forward, but rarely developed or focused on in the weight room.

It starts with contact on the ground with one leg. If the contact is fast enough, it will help pull the hip of the swing leg forward 10 degrees. With the plant leg fixed on the ground, it forces the other half of the gluteus medius to do its other job, which is to rotate the hip forward once the knee is under the hip.

A simple way to understand this concept is to grab something heavy and try to do a biceps curl. If the weight is too heavy, it won’t move—but that won’t stop the contraction. The biceps will continue to fire, which is why your shoulder will roll forward. This concept would coincide with Marcus Pandy’s paper “How muscles maximize performance in accelerated sprinting” where the gluteus medius has an important role in acceleration. One end of the limb is locked on the ground, and as a result the other hip will rotate forward.

How can we train this? I like to do cable pulls with a cuff around the ankle. Usually, people will grab something to keep balance. It is an intralimb exercise because the hand supporting the body provides stability. If I take the hand off the support, now my opposite thigh has to support the hips to pull the leg through and it becomes an interlimb exercise. I like to add a step to excite my cross-crawl reflex.

Video 4. Step and go.

To add the hip rotation, I would do the same exercise, but block the opposite hip and allow the swing leg hip to rotate 10 degrees forward and back, forcing the plant leg glute med to do the work. There is some good research to show that the rotation of the hips is actually what improves our stride length.

To make it more interlimb, I would eliminate the block and use a step. I can attach my ankle or my thigh: ankle would be more rec fem and thigh would be more glute med. Regardless of my attachment point, I would want to step up to a box so I have an end target to really focus on my hip rotation.

Video 5. Hip Box

In terms of logistics for these exercises, I like a couple weeks of high force for 4-5 reps at a 3-5 sec contraction. 2-3 sets should be plenty. That’s followed by 2-3 weeks of some power movements for higher reps. A medium rubber band is an easy choice with the peak resistance at a point where the attached knee is passing the stance knee. I finish with really fast movements for reps of 20-30.

Since you’re here…
…we have a small favor to ask. More people are reading SimpliFaster than ever, and each week we bring you compelling content from coaches, sport scientists, and physiotherapists who are devoted to building better athletes. Please take a moment to share the articles on social media, engage the authors with questions and comments below, and link to articles when appropriate if you have a blog or participate on forums of related topics. — SF

Before you dive in further, I want you to envision a collision sport athlete who personifies speed. That athlete who leaves opponents in their rearview mirror. Who came to mind? As my background is rugby, my brain goes directly to Smokin’ Joe Rokocoko.

Next, I want you to envision a bruising ball carrier or defender—someone who more likely than not has sent someone to hospital. Who you got this time? I think of the late, great Jerry Collins.

Now, think of an athlete who has both traits, who if required could easily run around their opposition, or conversely run right over them. Who comes to mind? In rugby there is no going past Jonah Lomu.

As an S&C coach working in a collision sport my goal is to try and create powerful athletes. Athletes who can use their speed, strength, or both to win the collision zone. One way that I do this is with the 1080 Sprint.

I have been working with the 1080 Sprint since 2019, and in that time I have been able to learn from coaches who have shared their experiences with the technology, including Cameron Josse, Chris Korfist, Matt Tometz, Jacob Cohen, and Kyle Davey. I also wrote an article for Simplifaster on how I use the 1080 Sprint to perform resisted sprints and profile athletes using the software tools.

One thing missing in all this, however, is benchmark data relating to sprint times, velocities, and momentum. There is a plethora of data on sprint times and velocity measured using speed gates and GPS, yet there is a lack of data out there from coaches using the 1080 Sprint. Regarding sprint momentum and rugby union, there are two published papers: one conducted on amateur athletes¹ and the other on professional junior and senior rugby athletes². In this article, I will share insights into sprint momentum, velocity, and split times recorded using the 1080 Sprint.

*This article shares general benchmarks and insights into sprint performance using the 1080 Sprint, which are intended to support the broader coaching community and cannot be directly applied in a way that would compromise my team’s competitive advantage.

Athlete Data & Methods

I analysed sprint performance data from 38 of my professional rugby players over a 20m distance, collecting split times, average velocity, and peak velocity data for each 5m split. I then calculated the momentum using the athlete’s body weight (both average and peak momentum).

The athletes completed 20m sprints indoors on a synthetic surface while wearing running shoes. This data was collected during the first testing session of each year over the past two seasons, with the best result from each athlete’s two 20m sprints used for analysis. Although I considered extending the distance by an additional 5m, I kept it at 20m to ensure the athletes had sufficient space to decelerate safely and could focus on giving maximal effort without hesitation.

All analysis was done using JASP³ and finding JASP in 2024 has been a godsend. I am by no means a whiz with stats, but using JASP has been a walk in the park compared to R and Python. Simply upload your data (in CSV format) into JASP, and the user-friendly software will help make the analysis of your data a breeze.

Rugby Union 101

For those of you not familiar with Rugby Union and the playing positions, here is a quick rundown.

Rugby union is a collision sport played over two 40-minute halves (80 minutes total). There are 15 players on the field (100m x 70m) for each team, and eight reserves on the bench. In international rugby, once a player is substituted, they cannot go back onto the field of play unless for an injury. All players play on attack and defence, and play continues until a stoppage is called by the referee due to an error such as a knock on (player dropping the ball forward), a forward pass, a penalty, or the ball goes out of bounds. The aim is to score points via a try (5 points) which is where you ground the ball in the opponent’s goal, or kicking the ball through the posts via a conversion (2 points) after a try is scored, or a penalty (3 points), or drop kick (3 points).

The Forward’s Group

These players are typically larger and stronger than the Back’s group. One of the main differences between the groups is that Forwards perform in the scrum and lineout and try to gain and maintain possession through tackles, rucks, and mauls. They engage in more collisions than the Backs throughout the match² and work in smaller spaces. Backs, on the other hand, are generally faster, more agile, and more responsible for passing, running, and kicking the ball to create scoring opportunities, often operating in larger open spaces.

• Front Row comprised of #1, #2, and #3. These guys pack down in the front row of a scrum and lift the jumpers in the lineout. We colloquially call them “Piggies” because they are big dudes with no necks and you certainly don’t offer to take them out for lunch.
• #1 and #3 are Props and #2 is called the Hooker, who is responsible for throwing the ball in during the lineout. For my American readers, the Props are the physical equivalent of your Offensive Linemen, and in some teams the Hooker can be like a third Prop, or a smaller and more mobile athlete like a Back Row athlete.

The Second Row

Here you have #4 and #5. Their most important role is jumping in the line out. Diving a little deeper you have different roles for the Second Row depending on teams. #4 is generally lighter and a better jumper as he is quicker in the air. #5 is the bigger of the two and packs down in the scrum behind #3.

The Back Row

#6, #7, and #8—these guys are not as big as #1-5, but offer a blend of size and mobility. They can carry the ball, tackle, and have what we refer to as “hands” in that they are good at passing and can work in with the Backs. Physically, these guys are the equivalent of Linebackers in American football.

In the Backs group you have the Halves, with #9 the Halfback and #10 the Flyhalf. These guys are the like the Quarterbacks, driving the team around the pitch and deciding when to run, pass, or kick. Physically, these guys tend to be the smallest players on the field.

You then have #12 and #13 and together they form the Centres. These guys can have multiple roles depending on the team. They can be big ball carriers and hard hitters on defence or act as a backup Flyhalf in that they can pass and kick. Generally, you would have one of each type on the field at the same time. Physically, these guys are the biggest of the Backs and would be like tackle-breaking running backs in the NFL.

The last Backs group are the Outside Backs (or Back Three), with #11 and #14 (Wingers) and #15 (Fullback). Your Wingers are your fastest players on the field, much like Wide Receivers, and your Fullback is a player who can do it all: run, kick, pass, and tackle, as often he is the last line of defence when the opposing team makes a break.

Sprint Momentum Values by Playing Group and Position

Sprint momentum is an important metric in collision sports, as it is a combination of an athlete’s velocity and mass. An athlete with the higher momentum should have a better chance of winning collisions (not taking into consideration technique).

Sprint momentum is an important metric in collision sports, as it is a combination of an athlete’s velocity and mass. An athlete with the higher momentum should have a better chance of winning collisions, says @jonobward. Share on X

Monitoring momentum gives us coaches a better understanding on an athlete’s physical development, as it tells us if the changes in velocity and body mass are beneficial.  For example, if my athlete improved his speed from 9.2m/s to 9.3 m/s, yet dropped 3kg in doing so, is this beneficial? Is he still robust enough to win the collision zone and withstand the repeated hits? Conversely, imagine another athlete gained 5kg over the year, but his max velocity dropped from 8.9 m/s to 8.6m/s. Has this increase in body mass made them less explosive and mobile around the field? Whilst they may be more dominant in the collisions, has there been a cost in terms of number of ball carries and tackles? This is what makes monitoring momentum better than just monitoring velocity or body mass—it can add a little more context to the athlete’s development.

Has an increase in body mass made the athlete less explosive and mobile around the field? While they may be more dominant in the collisions, has there been a cost in terms of number of ball carries and tackles? Share on X

Regarding my data below, I calculated momentum using both average and peak velocity over each 5m split to allow comparisons with systems like speed gates, which typically use average velocity over a given split to calculate momentum. You will find the mean weight (95% CI) for each position in Table 1. Table 2 shows the data for the Forwards and Backs, and Table 3 shows the data for each playing positions. When calculating momentum for each playing position I took the peak velocity.

When comparing my data to the research of Barr et al ², who examined momentum of professional rugby players over 40m, my findings mirrored what they found, with the forwards having significantly higher momentum than the backs (p=<0.001).

From above you can see that Front Row and Second Row have a higher momentum than other positions. For the Front Row, this is due to their increased body mass, and for the Second Row a mixture of their heavier body mass, and velocity, which you will see later in the article where I provide their velocities. They are followed by the Back Row and Centres, with the Outside Backs and Halves bringing up the rear.

Research by Mann et al ⁵ in college football athletes stated that momentum is a better metric to track than velocity alone, since velocity improvements are shown to stagnate in college football athletes ^6,7 yet body mass consistently increased. However, working in Rugby, and specifically in France, I have found that improvements in velocity can made in senior professional rugby. Speaking on my current situation here in France, one of the biggest reasons I believe this is due to the culture.

The culture of strength and conditioning, and long-term athlete development (LTAD) here in France is different compared to the anglophone countries such as the USA, UK, Australia, and New Zealand. Young athletes don’t have high schools that are kitted-out with state-of-the-art equipment, nor is there inter-collegiate sport like in the USA (NCAA). The majority don’t have access to the same level of coaching when they are younger. Whilst the S&C (and lifting) culture in France is on the up, France is still 10-15 years behind. I believe I am able to make significant improvements when working with my French athletes in part because many were not exposed to a structured speed program when younger.

To that end, below are some examples of the year-on-year change I have seen with my athletes.

The first example is an Outside Back, who increased his velocity and body mass (+2.7kg). As we can see in Graph 1, there is a nice vertical shift in the line graph between 2023 and 2024—this is what I would call a good responder and a job well done. On the field, we have also seen greater confidence in his ball carrying abilities (leading to a nice highlight reel of him putting opposing players on their ass).

In this second example I have a Centre/Outside Back who lost body mass (-3.1kg), but increased their velocity. Their loss in body mass was mostly due to fat loss, as observed in his lower sum of skin folds. He also increased his total body strength and fitness score (the 1.2km Bronco). So, whilst we saw a decrease in 5m momentum and 20m momentum, as a coach I am happy as physically he became a better athlete and we saw his production and involvement on the field increase too. This is why context is key, and a reason why momentum should not be viewed in isolation.

This last example is a Hooker who plays in the style of a Back Row. He lost weight (-1.6kg) and increased his velocity. Due to this, we saw his 5m momentum decrease, but his momentum in the 5-10m and 10-15m split increase. This athlete was in the similar boat to the athlete above, in that he lost fat mass but kept his strength levels and has seen more involvements in the match. Initially there were concerns about his loss in body mass affecting his ability to win the collision zone, but already this year he has scored four tries in close quarters, two of which he had multiple defenders trying to bring him down.

A final note regarding sprint momentum, I did have a handful of athletes who did not improve their momentum due to a loss in velocity or changes in body mass that were not beneficial. This presents a new challenge for me as I work to address this and help them return to their previous performance levels and ideally surpass them. When training to improve sprint momentum, I want to put in place a program that targets sprint velocity (acceleration and max velocity), in addition to gym programs that focus on strength, power, and lean muscle mass. For some players it can even be switching out gym (or half-a-session of gym) for off-feet conditioning sessions. I’m looking at my Polynesian athletes here, who were born as strong as an ox but take one look at fast food and pile on the kilos.

When training to improve sprint momentum, I want to put in place a program that targets sprint velocity (acceleration and max velocity), in addition to gym programs that focus on strength, power, and lean muscle mass, says @jonobward. Share on X

Average Velocity Values by Position

In Table 7 below you will find average velocity values—I know coaches using speed gates may want to make comparisons, as you may not have the capability to extrapolate peak velocity values.

Peak Velocity Values by Position

The peak velocity values are shown below in Table 8, and I conducted a statistical analysis to determine if there was a significant difference between the positions, and if so the effect size (Cohen’s d).

0–5m Peak Velocity Analysis

• Centres were faster than the Second Row (p = 0.045, d = 2.083), the Front Row (p = 0.001, d = 2.548), and the Halves (p = 0.033, d = 1.602).
• Outside Backs were faster than the Front Row (p = 0.003, d = 2.334).

5–10m Peak Velocity Analysis

• Centres were faster than the Front Row (p = 0.004, d = 2.294), and the Halves (p = 0.048, d = 1.521).
• Outside Backs were faster than the Front Row (p = 0.002, d = 2.486) and the Halves (p = 0.019, d = 1.713).

10–15m Peak Velocity Analysis

• Centres were faster than the Front Row (p = 0.014, d = 2.033).
• Outside Backs were faster than the Back Row (p = 0.037, d = 1.705), Front Row (p < 0.001, d = 2.716), and the Halves (p = 0.004, d = 1.998).

15–20m Peak Velocity Analysis

• Centres were faster than the Front Row (p = 0.004, d = 2.300).
• Outside Backs were faster than the Back Row (p = 0.004, d = 2.172), the Front Row (p < 0.001, d = 3.225), and the Halves (p = 0.015, d = 1.759).

The statistics show that the Centres and Outside Backs were significantly faster than other positions, depending on the split being examined. The Centres hit the highest velocity on average over the first 5m, then the Outside Backs took the cake from the from the 5m to the 20m mark. Whilst the Centres were able to stay with the Outside Backs over the first 10m, the Outside Backs accelerate faster over the second 10m split. What impressed me the most is the Second-Row group. These guys range from 195-200cm and are on average 117kg (258lbs), so to see them hit over 8.0 m/s in the last 5 metre split, and run faster than the Halves, was impressive. I would not want to be the one tackling them in full flight.

Split Times by Position

In Table 9 are the split times, and I also conducted a statistical analysis to determine if there was a significant difference between the positions, and if so the effect size (Cohen’s d).

0–5m Split:

• Outside Backs faster than Second Row (p < 0.001, d = 3.239) and Front Row (p < 0.001, d = 3.292).
• Centres faster than Second Row (p = 0.009, d = 2.510) and Front Row (p = 0.001, d = 2.562).
• Halves faster than Front Row (p = 0.019, d = 1.951).
• Back Row faster than Front Row (p = 0.040, d = 1.892).

5–10m Split:

• Outside Backs faster than Front Row (p < 0.001, d = 3.413).
• Centres faster than Front Row (p < 0.001, d = 3.168).
• Halves faster than Front Row (p = 0.009, d = 2.124).
• Back Row faster than Front Row (p = 0.039, d = 1.899).

10–15m Split:

• Outside Backs faster than Front Row (p < 0.001, d = 3.372).
• Centres faster than Front Row (p < 0.001, d = 2.794).
• Halves faster than Front Row (p = 0.010, d = 2.111).
• Back Row faster than Front Row (p = 0.036, d = 1.919).

15–20m Split:

• Outside Backs faster than Front Row (p < 0.001, d = 3.236).
• Centres faster than Front Row (p = 0.006, d = 2.203).
• Halves faster than Front Row (p = 0.023, d = 1.908).

Across all 5m splits, the Backs were significantly faster compared to the Front Row, with the Back Row also significantly faster than the Front Row over the first 15m. The Second Row were significantly slower than the Centres and Outside Backs over the first 5m. However, from the 5 to 20 metres, there was no significant difference, and they even managed to run a faster 15-20m split than the Halves, and the same time as the Centres. Wow!

Additionally, sprint timing comparisons between the speed gates and the 1080 Sprint is ill-advised. In my last article (near the end), I provided a research paper, and my own data, showing that it is not possible. There needs to be consistency in timing methods when tracking performance over time, so pick one and stick to it.

Conclusion

Sprint momentum is beneficial in collision sports like rugby union, where both velocity and mass contribute to an athlete’s effectiveness in the collision zone, and monitoring sprint momentum provides more context than monitoring velocity or mass alone.

In rugby there are significant differences in momentum across positions, with forwards, particularly the Front Row and Second Row, having higher momentum due to their larger body mass. Share on X

In rugby there are significant differences in momentum across positions, with forwards, particularly the Front Row and Second Row, having higher momentum due to their larger body mass. In contrast, the Backs, especially Outside Backs and Centres, hit significantly higher velocities. The individual athlete data (Graph 1-3) shows the nuanced nature of momentum, where changes in body mass and velocity need be contextualised to determine their impact on performance.

Since you’re here…
…we have a small favor to ask. More people are reading SimpliFaster than ever, and each week we bring you compelling content from coaches, sport scientists, and physiotherapists who are devoted to building better athletes. Please take a moment to share the articles on social media, engage the authors with questions and comments below, and link to articles when appropriate if you have a blog or participate on forums of related topics. — SF

References

1. Zabaloy, Santiago & Giráldez, Julián & Gazzo, Federico & Villaseca-Vicuña, Rodrigo & González, Javier. (2021). In-Season Assessment of Sprint Speed and Sprint Momentum in Rugby Players According To the Age Category and Playing Position. Journal of Human Kinetics. 77. 10.2478/hukin-2021-0025.

2. Barr, Matthew & Sheppard, Jeremy & Gabbett, Tim & Newton, Robert. (2014). Long-Term Training-Induced Changes in Sprinting Speed and Sprint Momentum in Elite Rugby Union Players. Journal of strength and conditioning research / National Strength & Conditioning Association. 28. 10.1519/JSC.0000000000000364.

3. JASP Team. (2024). JASP (Version 0.19.2) [Computer software].

4. Paul, Lara & Naughton, Mitchell & Jones, Ben & Davidow, Demi & Patel, Amir & Lambert, Mike & Hendricks, Sharief. (2022). Quantifying Collision Frequency and Intensity in Rugby Union and Rugby Sevens: A Systematic Review. Sports Medicine – Open. 8. 10.1186/s40798-021-00398-4.

5. Mann, Bryan & Mayhew, Jerry & Lopes dos Santos, Marcel & Dawes, Jay & Signorile, Joseph. (2022). Momentum, Rather Than Velocity, Is a More Effective Measure of Improvements in Division IA Football Player Performance. The Journal of Strength and Conditioning Research. Publish Ahead of Print. 10.1519/JSC.0000000000004206.

6. Jacobson, Bert & Conchola, Eric & Glass, Rob & Thompson, Brennan. (2012). Longitudinal Morphological and Performance Profiles for American, NCAA Division I Football Players. Journal of strength and conditioning research / National Strength & Conditioning Association. 27. 10.1519/JSC.0b013e31827fcc7d.

7. Miller, Todd & White, Tony & Kinley, Keith & Congleton, Jerome & Clark, Michael. (2002). The Effects of Training History, Player Position, and Body Composition on Exercise Performance in Collegiate Football Players. Journal of strength and conditioning research / National Strength & Conditioning Association. 16. 44-9. 10.1519/1533-4287(2002)016<0044:TEOTHP>2.0.CO;2.

Parents and coaches of child athletes are in a relentless search for the holy grail of maximizing sport performance. Often, this leads to early sport specialization, neglecting to see the value of a long-term athletic development approach. As a coach to athletes of all ages (5-18), I frequently see the lack of general fitness (strength, power, endurance) in today’s youth.

Considering that general fitness is the foundation on which sport skills are built, children (ages 6-9) who participate long-term in a strength and conditioning program (S&C) will realize a lifelong performance advantage. A few of those key advantages are:

• There is a developmental Window of Opportunity you can tap into for children between the ages of 6-9 years old.
• Establish a lifelong neurological advantage through consistent strength, power, and plyometric training.
• S&C programs condition athletes for the physical demands of competition in a controlled environment and make them more resilient to injury.
• General fitness is the foundation on which sport skills are built.

Video 1. Jumping and solving movement challenges in a range of patterns and planes takes advantage of the early window of opportunity to learn movement skills.

Neuroplasticity

Child development experts have established that children display a high degree of neuroplasticity—the ability of the brain to change and learn. Oftentimes, this is brought up when discussing childrens’ ability to acquire language more quickly than older people. Less understood is the key role the brain plays in athleticism, strength, and power performance.

Every movement we make is controlled by the brain. When a person begins strength training, the initial gains are a product of the nervous system becoming more coordinated and efficient. Increasing muscle size is a much slower process—typically taking at least 8-10 weeks of consistent training and nutrition—and is less significant in children. When we see Usain Bolt sprint the 100-meter dash or Michael Jordan dunk from the free throw line, we are seeing the expression of a supercharged nervous system.

As with language acquisition, children can increase strength and power at a remarkable rate and develop a physical potential that would not be possible if training is delayed until adolescence. This critical age range between the ages of six and nine is known as a Window of Opportunity.³

As with language acquisition, children can increase strength and power at a remarkable rate and develop a physical potential that would not be possible if training is delayed until adolescence, says @PinneyStrength. Share on X

Misconception

A popular misconception that has been thoroughly debunked is that S&C will stunt a child’s growth.¹ I find it interesting that nobody thinks twice about children competing in sports, but weightlifting is deemed dangerous.

Video 2. Introducing medicine balls, kettle-bells, bar-based movements, and other movement patterns.

In reality, attacking sports are actually far more dangerous than strength training because of the dynamic, intense, and unpredictable nature of competition. In contrast, S&C conditions athletes for the physical demands of competition in a controlled environment and makes them more resilient to injury.

Benefits

The benefits of S&C for children are profound, including physical, academic, and social-emotional growth. Physical benefits are the most obvious:

• Improved speed, power, strength, and coordination.
• Enhanced sport performance.
• Better conditioned for demands of sport/injury prevention.
• Increased bone mineral density.^2,5,8

Less obvious are the academic, behavioral, and social-emotional benefits. Children who are more physically active perform better academically, including better grades, attendance, and classroom behavior.⁷ Moreover, consider the social and psychological benefits of being a competent athlete, such as strong social connections, improved communication skills, and boosted self-confidence.⁴ All of these are advantages when navigating through adolescence, and support the development of a well-rounded individual.

Ground Rules

Guidelines for training children include focusing on quality over quantity, being positive and encouraging, and not forcing them to work out. The goal is to create positive associations with training to promote a lifelong passion for fitness. Children are ready to train when they have the desire and ability to practice skills attentively. When a child loses interest in a training session, simply suspend the session and tell them what a great job they did.

The goal is to create positive associations with training to promote a lifelong passion for fitness. Children are ready to train when they have the desire and ability to practice skills attentively, says @PinneyStrength. Share on X

A few things I do with my kids to make training more engaging are setting a 10-minute timer (so they know the session will be short and sweet), playing upbeat music to enhance the environment, and celebrating when they hit personal records. There are times when I can tell my kids are not interested in a structured workout in the garage gym—in these cases, we’ll go to the backyard and work on sports skills and I’ll attempt to sprinkle in exercises as well.

Secret Sauce

When I think of an athlete, I think of someone who is coordinated and explosive. To this end, strength, power, and plyometric work are essential. This is the low hanging fruit that can separate young athletes from their peers and establish a lifelong neurological advantage.

The good news is that this type of program is extremely practical, focusing on the things that really move the needle, and require minimal equipment and time. I do these workouts with my kids out of my garage gym with medicine balls, a squat rack, and a dip bar. The power-packed exercises are sprints, broad jumps, hops, modified push-ups, inverted rows, pull-ups, squats, and leg lifts. Exercises are performed for 5-15 reps in a circuit fashion—cycling through exercises with minimal rest time—with an emphasis on quality technique. Two-to-three workouts a week is ideal, but in reality, some weeks you will only get one or none. Stay the course!

Video 3. Measuring broad jumps to boost intent and track progress over time.

Sprints and broad jumps are timed and measured as Key Performance Indicators to track progress and encourage maximum intent. Keep in mind, like strength and power gains, children’s growth is not linear. They grow in spurts. If a child is in a growth spurt, you can expect that it will impact their coordination and performance. It will take time for them to grow into their new bodies. Be patient and understand that consistent training will help accelerate them through the awkward stages.

If a child is in a growth spurt, you can expect that it will impact their coordination and performance. It will take time for them to grow into their new bodies, says @PinneyStrength. Share on X

Sport participation is vital to developing sports-specific skills and learning to compete. Children need to become accustomed to game speed and intensity, and the mental aspects of competitions (e.g., dealing with nerves, being a team player, learning to fail, etc.). I am an advocate for kids playing multiple sports to develop a variety of skills. Early sport specialization will lead to improved performance in the short run, but the long-term dangers are burnout and overuse injuries.⁶

The truth is, many youth athletes over-compete and under-train. General fitness (strength, power, endurance) is the foundation on which sport skills are built. Therefore, developing greater strength and power will result in an athletic advantage. Keep in mind that sport contests are often decided by just a few explosive plays. Impact athletes are stronger and more explosive than the competition. These athletes are game changers.

Sample Workout

Set a timer for 10-minutes and cycle through as many rounds as possible:

1. Pogo Hops x 20
2. Modified Push-up x 10-15 (I use an elevated bar on a squat rack)
3. Inverted Rows x 10-15 (using the same bar)
4. Leg lifts x 5-10 (using dip bars)
5. Squats with 5-10 lb. medicine ball x 5-10
6. Broad Jumps x 3

Test broad jump and sprint time frequently to track progress.

References

1. Barbieri, D., Zaccagni, L. (2011). Strength Training for Children and Adolescents: Benefits and Risks. Collegium Antropologicum. 37(2): 219-22.

2. Behringer, M., Vom Heede, A., Matthews, M., & Mester, J. (2011). Effects of strength training on motor performance skills in children and adolescents: a meta-analysis. Pediatric exercise science. 23(2), 186-206.

3. Caulfield, S. P., Smith, W. S. (2019). Windows of Opportunity. Developing Agility and Quickness. Second Edition: pp. 68 – 70.

4. Eime, R. M., Young, J. A., Harvey, J. T., Charity, M. J., & Payne, W. R. (2013). A systematic review of the psychological and social benefits of participation in sport for children and adolescents: informing development of a conceptual model of health through sport. The international journal of behavioral nutrition and physical activity. 10(98).

5. Faigenbaum, A. D. (2000). Strength Training for Children and Adolescents. Clinics in Sports Medicine. 19(4).

6. Jayanthi, N., Pinkham, C., Dugas, L., Patrick, B., & Labella, C. (2013). Sports specialization in young athletes: evidence-based recommendations. Sports health, 5(3), 251–257.

7. Michael, S. L., Merlo, C. L., Basch, C. E., Wentzel, K. R., & Wechsler, H. (2015). Critical connections: health and academics. Journal of School health. 85(11), 740-758.

8. Sortwell, A. (2020). Effects of Plyometric-Based Program on Motor Performance Skills in Primary School Children Aged Seven and Eight.

Since you’re here…
…we have a small favor to ask. More people are reading SimpliFaster than ever, and each week we bring you compelling content from coaches, sport scientists, and physiotherapists who are devoted to building better athletes. Please take a moment to share the articles on social media, engage the authors with questions and comments below, and link to articles when appropriate if you have a blog or participate on forums of related topics. — SF

A couple years ago, I wrote about the most unconventional thing we do in our track and field program here at Kalamazoo Central High School: the fly-by exchange in the 4×200 meter relay.

If you’ve ever seen this handoff in action, you know that it’s a bit…odd. The fly-by exchange inverts the traditional order of operations in which the outgoing runner takes off while the incoming runner chases him down to pass the stick, instead allowing the incoming runner to overtake his teammate. This places the onus to chase on the fresher, outgoing runner, who retrieves—rather than receives—the baton at full speed. It’s pretty slick—not only because it induces double-takes from those who haven’t seen it before, but also because it remedies several issues any 4×200 meter relay coach will be all too familiar with.

See, over the years, I’ve noticed that how a runner feels and looks at the end of a 200 can vary significantly from race to race. The most common symptom of this variability is that the outgoing runner, who is ready and raring to go, begins to run away from his tired teammate and then has to slow down in order to get the stick inside the zone. Other variations on this theme are that the outgoing runner, remembering having run away the last time, takes off turtle-slow from the jump; or that the incoming runner, being visited by the Ghost of Relays Past, has a vision of being left flailing, unable to catch his teammate, and panics, shouting “Slow! Slow,” destroying the relay time thusly.

The fly-by exchange inverts the traditional order of operations in which the outgoing runner takes off while the incoming runner chases him down to pass the stick, instead allowing the incoming runner to overtake his teammate. Share on X

When the incoming runner is allowed to overtake his teammate, he has only one job: keep running as hard as he possibly can. As a result, the outgoing runner has only one choice: sprint as fast as possible to catch him. The outcome is that both athletes are giving maximal effort at all times and the exchange doesn’t grind to a halt due to a missed connection. Anything we can do to minimize the deceleration of the baton through the zone will ultimately benefit the success of the relay. Since implementing this handoff with our boys’ team, our times have improved every year. This past season we broke a decade-old school record and finished fifth at the MHSAA State Finals.

For a more complete introduction to the fly-by exchange, feel free to check out my original article from 2022.

For the first three years of my tenure at Kalamazoo Central, we had an assistant coach overseeing the girls’ sprints, but due to staff turnover I started coaching our girls last season as well. In 2024, the first season implementing the fly-by exchange with our girls’ relay team, we ran almost a full second faster than the previous season, posting a best time of 1:46.99. We return several of our top sprinters to the team for 2025, and I anticipate an even better result this spring.

Before we go any further, now seems like a good time for some visuals, so you can see what this monstrosity looks like in action.

Video 1. The third and fourth leg of our 4×200 meter relay team practicing the fly-by exchange.

Since sharing my original article back in 2022, I’ve had countless conversations with other coaches about this method. Some are skeptical, most are curious, and more than a handful have begun to implement the fly-by exchange in their programs as well. Throughout the rest of this article, I’m going to sprinkle in some testimonials I’ve received from coaches who were brave enough to try the fly-by exchange, and kind enough to share their success with me. Across the board, those coaches who have adopted the handoff have been thrilled with the results.

Questions, of course, have come along with these success stories. And in addition to some of those questions others have asked, we’ve made some small modifications over the last couple of years to try to make this handoff as squeaky-clean as possible. The truth? Nothing is perfect. And as much as I would love to be able to tell you that this handoff is entirely foolproof, I just can’t do it. In fact, in 2023, we entered the state finals having run 1:28.00, which was the fastest time in Michigan up to that point in the season. On paper, we were favored to win…but as every coach knows, what it says on paper doesn’t always play out on the track.

We were sitting around third place heading into the final exchange, and we bobbled the handoff. Next thing I knew, the stick was rolling around on the track and the rest of the pack was headed into the homestretch while we could do nothing but watch the finish. We felt like we let one get away. It was a reminder that no matter what we do, the relays are volatile events and no matter what handoff method you employ, it always comes down to execution.

With that in mind, what comes next are some tips, cues, and considerations I hope will help to execute the fly-by handoff with as much consistency as possible and reduce the likelihood of heartache.

Video 2. Our 4×200 meter relay team at the 2024 MHSAA State Finals. We are in lane 4. Final time 1:27.38. As an additional viewing point, notice the team in lane 5 suffering the exact issue the fly-by exchange aims to address. Lane 8 also drops the stick due to an end-of-zone collision.

No matter what we do, the relays are volatile events and no matter what handoff method you employ, it always comes down to execution, says @TrackCoachTG. Share on X

Coaching Cues for a Better Fly-By Exchange

In its simplest form, the fly-by exchange is fairly easy to coach: every athlete should be running as fast as they are able at all times. But, timing always matters for a good exchange—so, we really try to make sure the outgoing runner’s takeoff is on point.

One way we have done this is by creating a bigger visual target to use as a go-mark. In my original piece, I recommended starting with marks at five and seven feet before the start of the zone and adjusting from there, depending on your athletes. We have expanded the box on both ends, making marks at four and eight feet for most of our runners. In Michigan we are only allowed to mark with chalk , and this makes the box easier for our athletes to see.

In addition to expanding the box of our go-mark, we have placed additional emphasis on anticipating the moment at which the incoming runner hits the box, rather than reacting to it. Relays give us a unique opportunity to cheat acceleration by beginning with a knee bend into a forward lean, and then taking off with a rolling two-point start. This, plus the visual cue of an approaching teammate—rather than the auditory cue of a starter’s pistol—gives us an acceleratory advantage we want to maximize.

Therefore, I coach our outgoing athletes to prepare for takeoff while their teammate is around 20 meters away. This means they bend their knees and get into an athletic position. As the athlete gets closer to the go-mark, they start their forward lean, transferring weight to their front foot. They anticipate their teammate hitting the mark, just like a quarterback anticipates where his receiver will be by the time the ball arrives. If executed with perfection, when the incoming athlete’s foot hits the mark, the outgoing runner is already into his first stride. If this sounds familiar, it must mean that you’ve read this article about the Bang Step for the 4×100 meter relay. Our concept is very similar, and it’s easy to verify on video to show athletes whether they’ve left on time.

Another adjustment I’ve made is coaching how the incoming runner presents the stick to his teammate. For whatever reason, our guys were holding the stick at shoulder height. Probably my fault. If there’s any height discrepancy between the two runners, the outgoing runner sometimes looked like he was reaching up to grab the baton, which was pretty awkward. I now coach our athletes to hold the baton out in front at around belly-button height, so that no matter the size of the athletes, the stick is easier to grab.

A common question among coaches I’ve talked to is “are you sure there’s enough room for two athletes to be side-by-side in the lane?” In short, yes, I am. But, we still have to be intentional. One of the things we work on a lot is the concept of lane ownership. The incoming runner must stay to the inside half of the lane with the stick in his right hand. The outgoing runner must stay to the outside half of the lane, grab the stick with his left hand, and then transfer the stick to his right hand upon exiting the zone.

I’ve drawn a line with chalk to divide the lane in two in order to teach this concept, and it’s something we drill every time we practice the handoff. As you can see in the image below, both athletes are inside the lane even when side by side. We have never been disqualified for running out of the lane lines in four years of running this race with a fly-by exchange.

If you’re teaching this handoff for the first time and you need to convince your athletes there’s room for both of them, just have them stand next to each other inside of a lane. You will find, more often than not, that there’s enough space.

Of course, there are rare occasions where there may not be enough room for two very specific athletes. For example, what if you have a 6’3” linebacker handing off to a 5’9” running back and both of them are wide-shouldered athletes? We had this exact situation last year. The solution? We simply made sure that those two athletes were not on back-to-back legs. One of them ran first, the other ran third, and our two narrower athletes ran second and fourth. But in most situations with most athletes, with appropriate attention to lane ownership, it’s no problem. And with our female athletes, this is a complete non-issue.

Relay Order Considerations

The distance of legs of the 4×200 varies:

• The first leg will run up to 210 total meters, from starting block through the end of the first exchange.
• The second runner, who will run from the beginning of Zone One all the way to the end of Zone Two, will end up sprinting 230 meters.
• The same is true for your third runner.
• Your anchor leg will sprint 220 meters from the start of their exchange zone through the finish line.

My preference is to maximize my fastest athletes and those who may have a bit better speed endurance on the longer legs of the race, which means I’m not having those kids run first. So, who does run first? Remember all that stuff I said about outgoing runners anticipating their teammate’s arrival and leaving at the appropriate time? Whichever athlete is the worst at anticipating is probably your safest bet to lead off. Now, all he has to do is give the baton. But what if your fastest kid is also your worst anticipator? Look, there are a million variables. You are the expert on your own personnel.

For me, the things I’m most concerned with when it comes to relay order are the length of each leg, each athlete’s ability to anticipate their incoming teammate hitting the mark, each athlete’s 200 PR, their race-finishing abilities, and how much they hate to lose. Know your kids, experiment with your relay order, and decide what works best for you. We typically experiment until a week before our conference championship meet, then lock our relay order in for the rest of the season.

I can’t say for sure what this year’s relays will hold for us, but I will say this: if you see us at a meet, when the 4×200 relay comes around, keep your eye on Kalamazoo Central. We’ll be the ones doing the goofiest handoff you’ve ever seen, and if all goes according to plan, we’ll be celebrating in June. I hope you will, too, which is why I’m sharing the method behind my madness. Track is a beautiful sport: my team’s success does not depend on your team’s failure. When kids succeed, we all win. I’d encourage you to give this method a chance. After all, as numerous coaches have pointed out, it’s just crazy enough to work.

I’m not writing this article to introduce a novel assessment—the countermovement jump (CMJ) has been used for longer than I’ve been a coach and numerous practitioners have been applying it as an assessment for much longer than me! I do, however, find it interesting when I speak to other coaches about some of the nuances of measures I take and they are curious about and surprised by things I assumed were common knowledge. This is not to boast—the same thing happens in reverse with almost every coach I speak to—but I wanted to take this opportunity to share how I approach one of the most common assessment measures in all of performance.

Some of the “precautions” I take might seem trivial, but the consistency and reliability of data is of the utmost importance IF we want to assume any actionable insight from the data. On a recent episode of the podcast I co-host with Mike Sullivan, Move The Needle: The Human Performance Podcast, we had a conversation with Adam Virgile of the Los Angeles Clippers that included a fairly long discussion on “clean data.”

This helped to reinforce that I am correct in thinking that the way you collect data is as important as the way you interpret it. You cannot have accurate interpretation without clean collection. This is not to say that we in the performance field can expect to collect data in the same way as in a research setting; however, I think we can appreciate the rigidity of that model and attempt to collect our data in a similar fashion, even while being in a much more chaotic environment.

The way you collect data is as important as the way you interpret it—you cannot have accurate interpretation without clean collection, says @Huntereis_sc . Share on X

If there is not a level of consistency within your testing procedure, you may be better off not even wasting athletes time in performing CMJs on a force plate, because you will be unable to glean any information from the data. Instead of trying to tease out adaptation or fatigue, these outcomes have to compete with variations that could come from jumping at different times of day, participating in different warm-ups, being given different cues on how to jump, or even simply being awarded feedback or not.

Beyond collection protocols, I believe there are some misconceptions about the use of the information. In a recent post I put out on Twitter and Instagram—showing pregame CMJs I do with my athletes—there were a host of questions, some of which centered around the CMJ potentially predicting injury or dictating game availability/playing time. The data we glean from force plate assessments are one ingredient in the elusive mystery of “readiness.” There are a host of other factors that have to be considered, like sleep, nutrition, arousal, etc., and any taken in isolation only illuminate a small portion of the overall picture.

Throughout this article, I will touch on how I try to create as close to ‘research-grade’ testing procedures as possible to generate actionable pieces of information. We’ll dig into interpreting data, from the raw Force Time curves to some of the most important metrics. We’ll also look at certain types of curves and the information you’re able to collect from these. I hope this article does what countless individuals have done for me: expedite the learning process with force plate assessments and allow you to be an even greater asset to the coaches and athletes you work with.

Consistency

As I alluded to already, coaches may not appreciate consistency as much as they should, since it is an imperative piece to this equation. I could just dig right into the fun stuff, dissecting curves and watching metrics change over time; if, however, we miss the execution of testing, those other things don’t even matter.

Some of what I talk about may have you saying “Alright, that seems like overkill”…and some of it may be! However, if you have the opportunity to create consistency within your testing procedure, regardless of how nominal it seems, do it. Consistency needs to begin the minute athletes come under your instruction. There are multiple factors that we need to consider when preparing to administer a test of any sort, but especially on force plates.

The first? Arousal level.

The energy you bring to the room can affect the way your athletes perform on a test.

If you are quiet, speaking in a monotone, and have no energy throughout an entire training session, your athletes will feed off that. If you have the opposite—energy, “juice” as some may call it—that will immediately add to your athletes’ energy levels. As a personal philosophy, I try to be as consistent as possible with my energy, regardless of day, regardless of jumps on the force plate or not.

Consistency needs to begin the minute athletes come under your instruction. There are multiple factors that we need to consider when preparing to administer a test of any sort, but especially on force plates, says @Huntereis_sc. Share on X

The next piece to think about from an arousal perspective is the environment in the room. Is Waka Flocka blasting? Or is Drake playing at a Waiting Room volume? Do you invite and incite teammates to talk crap to each other as they’re jumping, or do you make it more of a 1-on-1 environment, while teammates are distracted doing something else? All of these pieces may not be 100% controllable, but your energy and the environment you create in your weight room on days that you know you are planning to collect jumps, is.

The next consideration is what type of preparation your athletes do before they jump. For example, I’ve found that comparing jumps during a fairly traditional lift—with limited jumping or running beforehand—to jumps after 20-30 minutes of plyometrics and speed development  is like comparing apples to oranges. And what if you also jump pre-game? The jumps from these three scenarios will not even be within the same realm. Now, this is not to say DON’T jump in different scenarios; you just have to be mindful that you should compare jumps of like scenarios to one another.

As an example, we perform “Speed Development” sessions year-round (throughout the off-season and in-season). The off-season sessions may end up being slightly higher volume, but they consist of similar components and last anywhere from 30-35 minutes. Therefore, we will perform jumps after those sessions year-round in an attempt to have a measure throughout the entire year that I know is coming after the same scenario. We also will jump pregame during warm-ups.

Do I compare pregame jumps to post-speed jumps?

No. I can confidently say that pre-game jumps will result in improved metrics across the board. Is that to say athletes had magical adaptation overnight? Obviously not—they are in a new environment, with a new preparation scenario, and heightened arousal levels. Therefore, performance is altered.

Anybody reading this who has ever worked with me knows how much of a stickler I am about the next facet of consistency. The way in which we cue our athletes before their jump and the way we report the information from their jumps may be the most important piece to this entire equation. When my athletes step on the plates, I repeat the same exact information every time.

• First, I tell them to hold still until the ‘quiet period’ on the Hawkin Dynamic plates is registered.
• Then I simply say “fast and high.” That is the athlete’s cue to jump.

During an athlete’s initial times jumping with me, they may be confused by the cue fast and high, because up until this point, most vertical jumps they’ve performed in any capacity were for height, without any regard to “fast.” So, a slight explanation may be needed on the “fast” portion.

I believe the consistency of what you say is ultimately more important than what you say, but if you want to make observations from rate-dependent metrics and output-driven metrics, you should cue some element of both. To eliminate the importance of cueing consistency and to show why both elements of rate and output cueing should be used, I ran an experiment on two individuals.

The way in which we cue our athletes before their jump and the way we report the information from their jumps may be the most important piece to this entire equation, says @Huntereis_sc. Share on X

The results from the first experiment are above. I included the Force Time Curve and a metric associated with output (Jump Height), rate-dependent metrics (Time to Takeoff & Braking Phase Duration), a ratio metric (mRSI) and finally a strategy based metric, Countermovement Depth. This experiment is to show the relevance of being intentional with your cueing! The first jump on top the cue was purely focused on jump height, as the athlete was instructed to “Jump as high as you can!” We can see the associated Force Time Curve and metrics with this cue.

The next jump, depicted by the graph below, was performed after the cue “Jump as fast as you can!” We can see the difference in the metrics between the two jumps. Did physical qualities magically change between jumps? Obviously, no. However, the focus, intent—and therefore the strategy that was chosen—were drastically different.

The results from my second experiment are above. For the first jump I gave the cue “Jump as high as you can.” The associated results are seen on top. Before the second jump, the athlete was told “Jump as fast as you can.” The results from this are shown on the bottom graph—as you can see, we are able to manipulate athletes’ strategies by the words we choose.

From this portion of the assessment, I’ve wrestled with what to report to the athletes. Again, the consistency probably provides more value than the specific report, but there is obvious significance in both. After each jump (typically we perform two), I report jump height. Now, you may say, well if you just report jump height, won’t that skew athletes to the “High” portion of the jump and draw them away from “Fast”? I wouldn’t disagree. But I’ve found that reporting, for example, both Jump Height and Time to Takeoff, creates an information overload with too much for athletes to comprehend, leading to over analysis.

I feel comfortable that hearing their jump height will help drive intent with the athlete and the cue of “fast and high” will continually remind them to get off the plates fast. After years of collection, I am even more comfortable with this method because I continuously see my athletes’ Time to Takeoff decrease over time with a gradual increase in Jump Height.

I understand this was an extensive explanation on the considerations that I believe create the most consistent and reliable data, and I hope it drives home the point that the way we collect data is as important as the way we interpret it, if not more. Interpretation is fuzzy if collection is inconsistent.

Interpreting Data

Most of you probably got to this section and thought “I wonder what metrics he is going to discuss?” If you thought about the metrics when I mentioned “data,” you may be disappointed in what the next portion of this article is going to entail. As opposed to digging directly into metrics, first we are going to start with looking at Force Time Curves. There was recently a question posted by @mtn_perform on social media asking “If you only could use one aspect of information from a CMJ on Force Plates, the metrics or the Force Time Curve, what would you choose?”

While I believe it would be tough to only rely on one or the other, I believe so much information would be lost in only focusing on the metrics. Before we begin to dig into how to interpret Force Time Curves, I would be remiss to not thank Jesse Green for introducing me to the power of looking at the curves. I would probably be like most, clicking past the weird, curved line that shows up after a jump and immediately start looking for the numbers. Before we talk about aspects of Force Time Curves, let’s break down each portion of a Force Time curve from a CMJ.

If you use Hawkin plates, they make it very easy to understand what the Force Time Curve is telling you. As you can see below, there are colors to depict the unweighting, braking, and propulsive phase of the jump. We’ll use their help so you can understand what is happening.

The video below also does a great job of showing the formation of a Force Time Curve in real time. I’ll allow these two examples to demonstrate the aspects of Force Time Curves before we take a deeper dive into the components.

Video 1. This video shows in real-time the formation of a Force Time Curve with an actual jump.

Before we start talking about each phase of the CMJ in isolation, it’s important to note that I’m a firm believer that each portion of a CMJ may not predict, but feeds, the next. A good ability to unweight feeds the ability to produce high amounts of force in the braking portion of the jump, and that force, if repurposed appropriately, adds to the propulsive phase.

Unweighting

If we look at the two pictures below, showing the unweighting phase of two different athletes, what do we notice?

On the right, the unweighting portion is what I’d consider incomplete. This is shown as the athlete is unable to unweight 100% of their bodyweight, with the curve not completely to the bottom of the graph. The picture on the left shows what I consider complete unweighting, where the athlete is able to almost completely reduce their bodyweight, seen by the lines being at the bottom portion of the graph.

If we think about why an incomplete unweighting phase is detrimental to the performance of a CMJ, my first consideration is that the athlete is missing out on potential energy. By completely unweighting, we have the ability to produce more force in the braking portion of the movement. One important note here is to determine if your athlete is unfamiliar with the intent of the movement or if they don’t have the capacity to completely unweight. This can be determined through simple instruction. I only recommend doing this during an athlete’s initial test (or two), if you notice an incomplete unweight.

This question of intent vs. capacity can be answered by simply explaining to the athlete what a complete unweight feels like: the rapid “pull” toward the ground, a free fall where the athlete has no “braking” tension until later in the downward portion of the movement. After a brief explanation and potential demonstration, allow the athlete to perform another CMJ with this new model to focus on. If the athlete now has an improved unweighting phase and the rate- and output-dependent metrics are the same as before, or even a little improved, we know that this was an intent and/or strategy issue. If the new strategy is utilized and the athlete’s other metrics are severely reduced, we know that they must not have the capacity to perform this dramatic of an unweight and physical development, specifically in the braking phase, must be addressed.

This braking phase improvement needs to happen from a physical and psychological perspective. If the athlete’s brain knows it does not have the capacity to slam on the brakes at the bottom of a complete unweight—and therefore handle the associated force associated—the unweight will be limited.

When dealing with an individual that has incomplete unweighting, exercises within the High Force portion of The Force System can be used (you can find more complete information about the Force System here). These are the same exercises that can and should be used to develop braking capacity; the emphasis behind the movements, however, can slightly change. When working to develop their physical ability and psychological confidence to completely unweight, the use of Drop Catches can have significant relevance. However, the focus here should not necessarily be on the intensity or Ground Reaction Forces (GRF’s), but on the intent with the movement.

This fits well in the progression of High Force movements as well—I’ve mentioned in previous articles that an athlete must first understand the importance of this rapid free fall, or pull toward the ground, to later have the ability to be exposed to higher GRFs. This initial emphasis contributes perfectly to the goal of unweighting improvement. Early on, you can use an exercise like a Trap Bar Drop Catch, with minimal additional load, with the sole focus of a complete unweight. This will not only contribute to an improved unweight in a CMJ, but set you up well to better develop the braking and GRF emphasis of the movement with Drop Catches later on as we increase intensity of the movement (and therefore expose athletes to higher GRFs).

Braking Phase

As we begin to look at the next portion of the Force Time Curve, we notice the braking phase. What I typically will assess first is the slope of the curve in this section—as you can see below, the two curves show athletes with two drastically different braking abilities.

The steep slope on the left depicts the ability of an athlete to be driving full speed and slam on the brakes—or even pull the “e-brake.” The gradual slope on the right shows an athlete that is driving full speed, slowly reducing speed by gradually taking their foot of the gas pedal, and slowly applying pressure to the brake.

The next portion of the braking phase that I assess is the magnitude, or absolute peak, of the braking/propulsive curve. This peak represents the force that the athlete is able to generate during the braking portion of the movement. I believe this magnitude offers the potential of high propulsive forces, leading to high outputs and impressive rate metrics (depending on the athlete’s ability to store and reproduce these braking forces effectively and efficiently). While it may not be completely necessary for athletes to produce the highest of braking forces in order for impressive outputs, I do believe it often contributes.

To build off of our training prescription for an athlete’s ability to unweight, the training prescription for improved braking follows a similar pattern. Allow the intent developed during the early implementation of Drop Catches to expose athletes to higher GRFs when the goal shifts to braking development. As we maintain the acceleration portion of the force equation, we can add mass to our drop catches to elicit higher GRFs—this will help to expedite the development of braking ability. As we follow the natural High Force progression, we can move into Depth Drops, where athletes can experience more than 10x bodyweight forces and deliver the most potent dose of braking or deceleration stimulus possible.

As we maintain the acceleration portion of the force equation, we can add mass to our drop catches to elicit higher GRFs—this will help to expedite the development of braking ability, says @Huntereis_sc. Share on X

At this point, we still haven’t even gotten close to leaving the ground! As I’ve said, each portion of a CMJ is built from the previous and right now we are at the bottom of the countermovement. The development that has occurred to this point will assuredly amplify the part of the movement that often gets the most attention: propulsion.

Propulsion

An important point to make with propulsion: if there are no constraints placed on the movement, then don’t worry about anything to this point. If you’re in a vertical jump competition, with no time constraints, load at whatever rate and depth produces the highest output. But sport is not a vertical jump competition and athletes almost always have a time constraint, therefore making our previous two sections vital.

As we begin to look at propulsion, I tend to examine the slope of this downward portion of the graph, depicted below.

As you can see from the graph above, this individual does a good job of unweighting, plus adds an impressive braking phase…but does not have a propulsive phase that matches, which is shown by the difference in slope of line from braking to propulsion (braking being almost completely vertical, with propulsion being much more rounded). This may be the case after training an individual with Drop Catches and Depth Drops, and now we can focus on training more concentric-based movements, like a Trap Bar Pull, or Overcoming Isometric, shown below.

Video 2. Both a Trap Bar Pull and Overcoming Isometric are more concentrically-oriented movements, compared to movements discussed earlier such as Drop Catches and Depth Drops. Once the foundation has been laid, with a focus on unweighting and braking, a shift to more concentric-type exercises can begin to orient the slope of the propulsive portion of the curve more vertically.

Types of Curves

Before we begin discussing specifics surrounding metrics, I wanted to take some time to discuss different archetypes of curves that you’ll typically see and what they mean. In most situations, you’ll see curves that resemble three shapes, which I classify as:

1. Unimodal
2. Bimodal Primary
3. Bimodal Secondary

An important note: while Unimodal and Bimodal Secondary curves are the two ends of a spectrum, it is not an all-or-nothing situation. For example, I will talk about Bimodal Secondary jumpers’ inability to fully leverage connective tissue to contribute to movement. That is not to say they don’t receive any contribution to their jump from connective tissue, I just believe it to be much less than a Unimodal Jumper. In the same regard, Unimodal jumpers are still going to utilize musculature to jump, but the percentage will be much lower than their Bimodal counterparts.

Let’s dig into each archetype of curve and what they mean.

Unimodal

This curve is best represented by one peak during the braking and subsequent propulsive phase. Elastic-driven athletes typically produce this Force Time Curve—these athletes typically utilize short countermovement depths to elicit a rapid stretch of connective tissue (i.e., tendons). Their connective tissue not only stretches rapidly, but has the capacity to store and repurpose all of that energy throughout the propulsive portion of the movement.

This movement strategy allows these athletes to not only leverage their elastic structures more effectively, but also removes the need to rely on bigger musculature to produce the majority of movement (like somebody that may demonstrate a deeper countermovement). P3, a performance group with facilities in Santa Barbara and Atlanta (and, in my opinion, one of the best—if not the best—performance facility in the world) released a research paper a few years ago relating to the three categories of jumpers that they have seen from their CMJ Force Plate assessments. From a kinematic standpoint, what they saw were three categories:

1. “Stiff Flexors”
2. “Hyper Flexors”
3. “Hip Flexors”

From my subjective evaluation, I’ve determined that most unimodal jumpers resemble the Stiff Flexor strategy (as seen below).

Figure 8. Picture of Stiff Flexor from P3’s “Different Movement Strategies in the Countermovement Jump Amongst a Large Cohort of NBA Players.” Open Access, Creative Commons License here.

So, what are the pros to this movement strategy?

Typically, these athletes’ rate-dependent metrics are good. They will get off the ground fast due to their shallow countermovement and reflexive nature of relying on connective tissue to be more of a driver of movement than musculature. I also believe this to be the most efficient way to produce movement. As we see from the Stiff Flexor picture, joints are stacked and loaded almost symmetrically, whereas the Hip Flexor is utilizing extreme hip flexion and minimal knee or ankle flexion.

As with anything, there are cons to this movement strategy (not a lot, though). Unimodal jumpers typically do not have as impressive of output-based metrics in a CMJ when specifically focused on Jump Height. I believe this is because a standstill CMJ, when height is the goal and time is not a constraint, will be best accomplished with a more muscular-driven strategy. Throw the time constraint back into play, however, and this ‘con’ goes out the window. When you see elastically-driven athletes, typically with narrow ISA, limited muscle mass, short muscle bellies, and long tendons, you likely have a Unimodal jumper.

When you see elastically-driven athletes, typically with narrow ISA, limited muscle mass, short muscle bellies and long tendons, you likely have a Unimodal jumper, says @Huntereis_sc. Share on X

Bimodal Primary

This curve occurs when there are two peaks during the braking and propulsive phase, with the first peak being higher. I believe this curve is representative of what I would consider a more ‘hybrid’ athlete. They are able to access and utilize connective tissue to help contribute to movement—seen by the first peak—but there is a ‘leak’ of energy present to where they then harness some of the force-generation capacity of larger musculature at deeper ranges of motion, which then provides a portion of propulsion as seen with the second peak.

Looking at P3’s model of CMJ jump strategy, I would say that most Bimodal Primary jumpers would resemble the Hyper Flexor strategy. I do, however, believe that a select few Hyper Flexors could potentially be Unimodal jumpers, if they possess elite braking and propulsive ability.

Figure 9. Picture of Hyper Flexor from P3’s “Different Movement Strategies in the Countermovement Jump Amongst a Large Cohort of NBA Players.” Open Access, Creative Commons License here.

The pros for a Bimodal Primary jumper are that they can take the best of both worlds from a movement strategy perspective. They are able to utilize connective tissue more than their Bimodal Secondary counterparts and also access and rely on the big musculature that Unimodal jumpers shy away from. Now this is not to say it is an ideal strategy, but it allows for access to various tissues which could help to accomplish a range of tasks within sport more effectively than other athletes.

The cons? Athletes using this strategy will often struggle with the rate-dependent nature that is often present in sport, especially compared with their Unimodal counterparts. This may be most evident in highly explosive situations in sports, such as a one-on-one between a wide receiver and a defensive back or a guard staying in front of another guard defensively on the perimeter in basketball. I believe the hybrid, Bimodal Primary jumpers are the hardest to distinguish by the ‘naked eye.’ Some may look slightly more elastically-driven, whereas some may have the ability to develop musculature more easily. Jayson Tatum, Jimmy Butler, Lebron James are all examples of what I’d consider Hybrid athletes.

Bimodal Secondary

This curve looks similar to Bimodal Primary with two peaks; a Secondary, however, will have a higher second peak. I believe this shows an extreme inability to unweight (and therefore brake) effectively, leverage almost any energy within connective tissue, and therefore repurpose it propulsively. These athletes want to ‘deal with,’ not utilize, the forces that are created during unweight and braking—and then in almost a separate movement, create propulsion.

If we look at something like an Eccentric Utilization Ratio (Ratio between CMJ and Non-CMJ), these individuals may be at or below 1.0—meaning their Non-Countermovement Jump is as good and in rare cases actually better than their Countermovement Jump (whereas a Unimodal jumper may be 1.2 or even 1.3). In relation to P3’s study, these could be the poor Hyper Flexors and oftentimes your Hip Flexors.

Figure 10. Picture of Hip Flexor from P3’s “Different Movement Strategies in the Countermovement Jump Amongst a Large Cohort of NBA Players.” Open Access, Creative Commons License here.

To be honest, for most sports, I don’t believe there to be many pros to this movement strategy. However, in select situations, like a lineman in American football, you may benefit with this more muscular-driven strategy because of the nature of the position and because of the movement occurring, typically, without a countermovement.

The cons to this movement strategy are probably pretty obvious—the athlete’s rate-dependent metrics are down and typically output metrics are also lower than other strategies. To distinguish your Bimodal Secondary and most muscular-driven movers in a sport like American football, just take a look at the offensive and defensive lines. It is much harder to find them in a sport like basketball, but they do exist!

Metrics

5000 words in and I’m finally getting to what a lot of you probably clicked on the link to read about. I hope that you have taken the time to read everything beforehand and didn’t just skip to this section, because I think there is crucial information in the first sections.

With metrics, coaches need to understand that you can’t just focus on one or even two metrics in order to paint the clearest picture of an athlete’s strategies, strengths, and weaknesses. This is because so many metrics have important relationships to other metrics—and if we don’t explore those other metrics, we can be clouded by the meaning of the metric of choice.

Let’s take at a couple examples:

1. Your athlete’s Modified Reactive Strength (mRSI) is improving!

• In this situation, be sure to look at the two metrics that are within a ratio to summate to mRSI, Jump Height, and Time to Takeoff (in Hawkin terms). Now, what if this increase is because the athlete is getting off the ground much faster but sacrificing jump height to do so? That may not always be a favorable adaptation or manipulation of strategy, but if we just look at mRSI and don’t understand how it can be broken down, we could be misled.

2. What if Time to Takeoff is not changing at all?

• We may be disappointed because we want our athletes to get off the ground faster. Well, by assessing countermovement depth, you may see that your athlete is actually moving through a greater ROM and achieving that new ROM at the same rate in which they previously achieved a shorter ROM. This therefore probably shows an increase in braking ability, with a more rapid unweight. To me, all of this equates as favorable adaptation—but if just looking at TTT, we could be disappointed.

Understand the relationship amongst metrics to better tease out adaptation, readiness, and fatigue amongst your athletes.

1^st Layer

I approach examining metrics in two layers. The first I believe to be the most relevant and easily digestible. My first layer of metrics include:

1. Jump Height – This will always be a staple metric. It is easy for everybody to understand and shows overall output. As mentioned, this is the one number I report to my athletes after each jump. (Small note: I do report everything in centimeters. Thank you to Cory Kennedy, a former boss of mine, for telling me real sport scientists speak in centimeters not inches!)
2. Time to Takeoff + Countermovement Depth – As stated above, the importance of looking at not just TTT but ‘qualifying’ it with Countermovement Depth.
3. mRSI – Once we know the components, we can assess mRSI to know if the changes in both of the above metrics equate to move mRSI in the right direction. Hopefully, Jump Height always goes up and TTT always goes down, but oftentimes you may see a subtle drop in one and a small improvement in the other and mRSI ‘qualifies’ that as a productive change or detrimental change.
4. Bodyweight – This is important to track for many reasons, but from a force plate perspective, it can be used for a qualifier for all change in metrics that occur. An individual could look like they’ve improved in every single metric, but if they’re 5 pounds lighter today, that may not be ideal and mean favorable adaptation has occurred. (With the one small caveat, that if we are attempting to improve body composition by losing fat mass and then we see an improvement in metrics, then this is a win-win!)

Jump Height will always be a staple metric. It is easy for everybody to understand and shows overall output—this is the one number I report to my athletes after each jump, says @Huntereis_sc. Share on X

2^nd Layer

My second layer of metrics include:

1. Peak Relative Propulsive Power – This is a metric talked about in a lot of sports and the correlation to sporting action. Therefore, I believe there to be relevance across multiple domains and within the 2^nd layer of metrics.
2. Peak Relative Braking Force – I like assessing this metric for overall braking ability. I have also often ranked teams that I work with in terms of highest to lowest in this specific metric and compared to subjective evaluation of on-court athleticism—there seems to be a fairly reliable correlation.
3. Peak Relative Propulsive Force – This allows me to see the whole picture, as it is the ‘other side of the curve’ from Peak Relative Braking Force.
4. Braking Phase – This really could be included in the first layer with TTT & CM Depth but for simplicity’s sake, I decided to add it by itself in the 2^nd layer. I believe this can help to tease out fatigue better than most, because now we are examining the time spent in just the eccentric portion of the movement, where we know that fatigue is typically more easily depicted when compared to the propulsive or concentric portion of the movement.

Conclusion

There you have it. If you would have told me 5 years ago that I’d be able to write a 6000+ word article on just the CMJ on force plates, I would have called you crazy. I say this not to point to my own knowledge, but to the fact that I truly am standing on the shoulders of giants. I am forever indebted to the individuals who have invested in me and continue to invest in me…even when I send them CMJ questions at 2am. They could easily ignore me, or not take the time to have discussions with me, but they do and I truly cannot thank them enough. Because of these people I am where I am today and am lucky that most of them have gone from “boss” or “coworker” to friend. So, thank you Jesse Green, Cory Kennedy, Kyle Sammons, Drake Berberet, and many more.

Force plate assessments may not determine who’s going to be the best at sport, or who’s going to get injured at your next practice, but allow this tool to help paint the picture you are trying to curate with the use of other pieces of technology, conversations you have, and evaluations you run.

As you can tell, I am very passionate about this topic and it feeds directly into my system, The Force System. If you have interest in hearing more about it and/or joining the waitlist for the next Force System Mentorship you can do so HERE. Also be on the lookout for a Force Plate course coming out in 2025 that will put a microscope on the things I spoke about here, training interventions based on force plate assessments, other meaningful tests to run on force plates and much more!

Since you’re here…
…we have a small favor to ask. More people are reading SimpliFaster than ever, and each week we bring you compelling content from coaches, sport scientists, and physiotherapists who are devoted to building better athletes. Please take a moment to share the articles on social media, engage the authors with questions and comments below, and link to articles when appropriate if you have a blog or participate on forums of related topics. — SF

Look, I’m going to say something relatively taboo in the field of Strength and Conditioning: many coaches just aren’t programming intelligently.

I’m not saying it’s their fault, I’m not saying they’re bad at their job, and I’m not saying they don’t deserve to be where they are. What I’m referring to is the lack of validation of different philosophies and their derivatives. It’s not the role of the practitioner to validate their methods—it’s their role to interpret research and land on best practices in order to develop the best athletes within the constraints of their organization. As a field, however, we cannot afford to stagnate by simply relying on tradition or anecdotal evidence. To grow in our individual careers, we need to be willing to audit our methods and improve our breadth of knowledge. Strength and Conditioning is a dynamic discipline, one that exists at the intersection of sports science, human performance, and organizational demands. To truly push the field forward, we must prioritize a culture of critical evaluation, open-mindedness, and continuous learning.

To truly push the S&C field forward, we must prioritize a culture of critical evaluation, open-mindedness, and continuous learning, says @connor_ryder30. Share on X

This means going beyond the surface-level application of ‘what works‘ and digging deeper into the why and how (see Image 1). Are we aligning our methods with the most recent advancements in physiology, biomechanics, and motor learning? Are we questioning outdated paradigms that no longer hold water? Are we, as coaches, willing to challenge our own biases and explore innovative approaches, even if it means stepping outside our comfort zone?

I think a lot of current S&C coaches are made uncomfortable when made to face these questions head-on. Formal education and standards are way too lax to prevent situations where someone who lacks a true, deep understanding of research application is put in a position to program training for athletes. I think that’s where I break away from the need for years of experience, in exchange for quality of experience. To remind myself of this concept, I always come back to this quote:

“Do you have 10 years of experience, or 1 year of experience 10 times?”

I have coached in a “long-term athletic development” (LTAD) environment at the collegiate level and in a “perform-now” environment in professional baseball. In the world of professional sports, I learned that I had to audit my process fairly frequently to check my own biases and give my athletes their best chance to win a job. Returning to the collegiate environment, I’ve realized there is a significant gap to bridge between the LTAD mindset and the continuous auditing of principles and methods, all in the ultimate pursuit of best practices within strength and conditioning.

In the world of professional sports, I learned that I had to audit my process fairly frequently to check my own biases and give my athletes their best chance to win a job, says @connor_ryder30. Share on X

I think everyone reading can agree that the athletes in our care deserve programming that is:

• Rooted in evidence-based practices.
• Adapted to their individual needs.
• Designed to maximize both their immediate performance and long-term development.

To achieve this, we need to collectively shift from interpreting research to actively contributing to it; and, admittedly, without expecting changes in compensation in the short-term. However, in an evidence-based field, compensation hasn’t historically been evidence-based; by contributing to growing the field, you’ll have much stronger leverage in negotiations against other job candidates or your organization. It’s hard to argue against hiring or giving a raise to a practitioner who has proven their worth in writing. There are different levels to contributions, but I’ll follow with three proposed solutions that cover the most common practitioner scenarios.

Image 1. Both when putting principles into practice and when conducting new research, validity and reliability are concerns that we need to take into account. There’s no way of knowing your training interventions and coaching are working without being heavily influenced by validated methods and creating reliability with your own implementation! (Image via “Validity and Reliability,” by Martyn Shuttleworth. Creative Commons License.)

Solution #1: Collaborate with the Campus Exercise Science or Data Analytics Program

If your school has an exercise science or data analytics program, you have a valuable resource for bridging the gap between academia and practice. This partnership can be mutually beneficial, combining your practical insights with their research expertise and access to equipment, software, and academic networks.

This is the solution that takes the most front-end work to establish, with support needed from many different disciplines to get it off the ground. However, it can also be the most beneficial, due to the amount of attention you can garner from stakeholders. For example, I once off-handedly mentioned the time it takes to analyze data to one of our athletic administrators, and they were immediately interested in getting our department connected to the statistics department to create a learning opportunity for their undergraduate students. In return, by taking analysis completely off the practitioner’s plate, some big projects could come to fruition, and it would be a massive step forward for our staff’s productivity.

Action Steps

• Collaborate with faculty to design applied research projects that align with your program’s needs (e.g., evaluating training interventions, load management, or athlete well-being).
• Engage students in hands-on research opportunities, using your program as a real-world lab for their coursework or theses.
• Use campus resources, such as labs or student workers, for testing variables like VO2 max, force output, or biomechanics analysis.
• Share findings with both academic and professional audiences through conferences, journal articles, or case studies.

Benefits

• By utilizing the people around you to design and execute the study according to your needs, you can manage the scope while still creating valid and reliable research.
• Leverage cutting-edge research tools without incurring extra costs.
• Contribute to academic publications that validate your methods.
• Strengthen the pipeline of future professionals by providing exercise science students with practical experience.

Solution #2: Maximize In-House Data Collection and Analysis

If your school lacks a dedicated exercise science program but you actively collect and analyze data in-house, you can still contribute to advancing the field by developing a systematic approach to research. Your internal data can be an invaluable resource for both the Strength and Conditioning community and academic researchers. This solution is best if you have a sport scientist on staff, or the ability to hire one!

Action Steps

• Develop a consistent framework for collecting and analyzing key performance metrics (e.g., GPS tracking, strength benchmarks, recovery data) (see Image 2).
• Partner with external researchers or organizations to validate and publish your findings, offering them access to your data in exchange for their expertise in study design.
• Present your in-house research at conferences or through professional organizations, even if it’s not formally published.
• Standardize your data collection process to ensure it’s replicable and robust, which increases its credibility for future collaborations.

Benefits

• Turn everyday performance monitoring into meaningful research contributions that can inform new practitioners.
• Build a reputation within your organization and outside as a leader in applied sports science.
• Strengthen your program’s data-driven approach, enhancing athlete outcomes, and your own personal credibility.

I constantly show my athletes the data I collect, which ensures they know that I’m still actively using the data and that my efforts to improve their performance are always evidence-based. Additionally, I open myself to new learning opportunities by sharing my practice, which helps me guide my future research by adding the perspective of my athletes and peers.

I constantly show my athletes the data I collect, which ensures they know that I’m still actively using the data and that my efforts to improve their performance are always evidence-based, says @connor_ryder30. Share on X

Solution 3: Lean on Interns and Personal Expertise to Conduct Research with Limited Resources

If your school has minimal resources, you can still make significant research contributions by using your expertise and tapping into the enthusiasm and manpower of interns. Focus on manageable, impactful projects that don’t require extensive funding or equipment. This solution is the direction where most S&C practitioners will be able to realistically go right away, but it shouldn’t discourage you from working towards Solutions 1 or 2!

If your school has minimal resources, you can still make significant research contributions by using your expertise and tapping into the enthusiasm and manpower of interns. Share on X

Action Steps

• Use your research background to guide interns in designing and executing small-scale studies that align with your programming goals (e.g., comparative analysis of different exercise selections).
• Focus on practical, low-cost research methods such as surveys, observational studies, or basic statistical analysis of existing performance data. Make sure your research group follows best practices for conducting research to avoid poor study design!
• Encourage interns to present findings at regional or national Strength and Conditioning conferences or submit them for publication in practitioner-oriented journals.
• Build a repository of case studies or research briefs that can be shared with the broader community.

Benefits

• Use your own expertise to overcome the limitations of funding or infrastructure.
• Keep interns engaged in the important, but less glamorous, side of S&C.
• Provide your staff with meaningful, resume-building research experience while auditing your own processes.
• Guide innovation and boost credibility despite resource constraints.

Pushing the field forward requires an honest assessment of what’s holding us back. I feel we’re too focused on utilizing established methods that may be outdated, we’re too dependent on the experiences of those who came before us, and at times, ignorant of what we can do to go beyond what is required of us now to get the things we want in the end.

Ultimately, the responsibility lies with all of us to raise the standards within the field of Strength and Conditioning. By committing to validated practices and making ourselves vulnerable to the scrutiny of others, we can collectively elevate the profession, and—more importantly—better develop the athletes who rely on us to help them succeed.

Since you’re here…
…we have a small favor to ask. More people are reading SimpliFaster than ever, and each week we bring you compelling content from coaches, sport scientists, and physiotherapists who are devoted to building better athletes. Please take a moment to share the articles on social media, engage the authors with questions and comments below, and link to articles when appropriate if you have a blog or participate on forums of related topics. — SF