Expression vs. Development in Rotational Sports

Elite-level athletes can show great feats of strength and power in extraordinary ways—and, at times, display these spectacular performances in areas they have never actually trained. This phenomena brings up an interesting concept in training, that of “expression” vs. “development.”

One specific example of this occurred in a case study¹ looking at baseball hitters’ proficiency in vision and reaction tests. In the tests, the best batters were able to also score very high on light-up board reaction tests, even though none of them had ever trained with the light-up boards before. This is a good representation of being able to express great general visual and reactive capabilities due to the many years of training to hit against challenging pitching.

But does this mean that training with the light-up board would be an effective means of training those players? Not necessarily. The best batters scored high in spite of never training with those methods before! This is where expression vs. development comes into play: tapping quickly and scoring high in a light-up board test is an expression of their ability to take in visual feedback and react by rapidly moving their hands to the right spot at the right time. They developed this capability through many years of batting practice. But enough of the baseball references…let’s dive into some training!

Expression in Training

Key performance indicators (KPIs) are an effective tool for evaluating whether training is producing the desired adaptations. For high-speed rotational athletes, KPIs often include tested performance in jumps, medicine ball throw distance and velocity, and other measures that can reflect the necessary neuromuscular qualities found in the sporting movement. For example, pressing power² is highly associated with swing power—therefore, a medicine ball chest pass for distance is an appropriate test to show that training is working!

Key performance indicators are an effective tool for evaluating whether training is producing the desired adaptations, says @billmills. Share on X

Video 1. Medicine ball throws for velocity can be used as a KPI to evaluate training.

The issue is determining how that improvement in expression occurred. Improvements in expression, or performance in an exercise, can come from:

1. Increases in overall force production from muscle groups highly involved within the movement pattern.
2. Increases in rate of force development from the neuromuscular system—increased contractile velocities or improved speed of the signal from brain to muscles.
3. Improvements in joint stabilization (tendon stiffness or muscle stiffness), which ultimately allows for a better transfer of energy throughout the kinetic sequence of the movement.
4. Improvements in muscle and tendon architecture, such as fiber-type shifts or appropriate tendon compliance, allowing for greater transfer of energy within the stretch reflex of the muscles when utilized in a high velocity fashion.
5. Improvements in technique or coordination specific to the movement being tested. This increases with measured reps as the athlete will often find the optimal pattern to achieve the highest score.

As you can see, the first four of the above areas can transfer well from one movement to another movement. There is great transfer to sport-specific power when one of those first four areas is developed in training. The last, though it can often account for great improvements in performance, does not transfer very well to other movements.

For example, let’s say an athlete performs a medicine ball rotational shotput throw³ in their training. They are performing a light load, high velocity movement that is rotational in nature, so it correlates well with throwing and swinging performance. Let’s say the first time the athlete does the exercise, they achieve a score of 30 mph. Over the next few sessions, they adjust their hand placement and elbow positioning so that they can push harder through the ball. The following week, after practicing it several times over the course of the week, they achieve a score of 34 mph. That’s a jump of four miles per hour from their initial test, but it does not mean they will now throw a baseball or swing a bat that much harder!

The adjustment in their technique is specific to the medicine ball throw.

When Is Expression Meaningful?

Many athletes will show huge improvements in the first few attempts testing with KPIs. Improvements in that short of a time period are likely all due to “beginner gains,” or improvement in coordination specific to the movement that comes about from the first one to three weeks of performing a certain exercise on a frequent basis. The mechanism behind these gains is the brain and central nervous system combining to create a more efficient signaling pattern to recruit the right muscle groups at the right time for both the stability to execute the exercise and the force to complete it.

As in the previous example, the athlete may find a better way to grip the implement or perform the technique in such a way that optimizes leverage, and therefore achieve greater performance in that way. Regardless, these early increases in performance are merely expressions that don’t reflect development or transfer to sport-specific power.

Let’s continue with the example of the athlete who saw huge “beginner gains” in the medicine ball shotput throw. In the months following, the athlete trains hard with rotational medicine ball throws, strength training, and other means of developing power. The shotput throw performance climbs steadily by one mile per hour every few weeks. This is where the expression begins to matter. These small, steady, and slow increases in performance are indications that neural and muscular qualities are the main reasons that performance is improving. This should transfer well to other rotational power movements, like swinging a bat faster or throwing a ball harder!

Video 2. MPH of medicine ball throws can be tracked to assess training progress.

Development in Training

Now that we’ve explored why expression does not always equal development, it’s important to dive into what development truly means. The reality is that development for one athlete might look entirely different for another. At the end of the day, all that matters is that training pushes adaptations for the athlete towards more power capabilities in their sport or more ability to resist injury.

The reality is that development for one athlete might look entirely different for another, says @billmills. Share on X

Let’s take the above example of a medicine ball shotput throw (after the “beginner gains” phase) and create a hypothetical scenario of training approaches for two athletes: Vinny and Frank. Both athletes will perform the med ball shotput throw in high volumes with high effort on a regular basis in their program. Let’s say no other form of upper body training was done to impact their throwing power and performance during this period.

In our hypothetical scenario, Vinny and Frank both throw 80 mph and want to throw 90 mph to improve their game and get noticed by college coaches. Both athletes want to throw harder, as harder fastballs are more difficult for opposing batters to hit, and college coaches will take notice if they show 90 mph on the radar gun. Vinny is very big and strong, but lacks rate of force development qualities—he has always struggled with throwing a baseball fast, in spite of his great strength in the bench press. Frank is skinnier and weaker—he has good velocity for someone his size, but that’s still not enough to stand out on the field and get noticed by college coaches.

Since Vinny lacks power at high velocities, the shotput throw fits his needs well. He’s able to see two to three mph jumps in performance every month of the offseason. By the end, he’s able to shotput throw a four-pound ball at 39 mph from a pitching start position. He concurrently trained hard with baseball throw velocity as well, long-tossing and throwing at high effort for the radar gun. This all increased his velocity to the point of breaking the 90 mph mark after just four months of training.

Frank, on the other hand was not able to improve his shotput throw very much. He did not gain any weight or strength in his upper body, and the medicine ball throws were not able to develop his biggest needs. His baseball throw velocity was only able to improve by a marginal amount.

This is a very rudimentary example and does not take into consideration other important areas for throwing velocity such as mobility, movement pattern, ball grip, and throwing deceleration capabilities. The goal of this example is to demonstrate how a force-velocity profile may differ greatly between two athletes, although their external output (80 mph throw) is the same. As such, not all athletes should follow the same routine.

A force-velocity profile may differ greatly between two athletes, although their external output is the same, says @billmills. Share on X

Video 3. Using a supine overhead throw with 10lb, 6lb, and 2lb medicine balls to create a force-velocity profile.

This is based on an actual story of an athlete I trained who came into the offseason topping at 83 mph off the mound and finished the offseason at 91 mph. He entered the offseason with a 285 lb bench press and 565 lb deadlift, yet could not throw the 4 lb ball harder than 32 mph in the shotput throw. We did not train any reps with the traditional bench press, but we focused on many forms of ballistic pressing. He had all the force in the tank, but he needed to develop his rate of force development. The medicine ball throws helped to develop and express! That, coupled with a strict, high-effort throwing regimen, helped him increase velocity by so much in such a short time.

Frank, on the other hand, is a fictional individual but represents a likely scenario for a lot of younger baseball players. They will find cool-looking, explosive exercises on social media and copy that into their training. All the while, they neglect strength training, proper diet, and sleep patterns…and that leads to them making little progress!

Are Medicine Ball Throws Expression or Development?

To best answer this question, you first have to look at the athlete’s biggest needs. If they are velocity-deficient—meaning they are strong but lack the ability to produce force at very high speeds—then medicine ball throws will be a perfect fit. However, athletes who are force-deficient, as many beginners are, will not see great development with medicine ball throws. They may be able to express great performance with medicine balls, but they won’t be able to see large improvements as a result of doing them. Those force-deficient athletes will need to train against heavier loads and with greater mechanical tension to improve muscle mass and overall force production. That’s how they will develop power!

Athletes who are force-deficient, as many beginners are, will not see great development with medicine ball throws, says @billmills. Share on X

Video 4. Supine overhead medicine ball throw.

What About One-Rep Max Testing?

This is another common area of argument on social media. Unless you’re competing for a powerlifting or Olympic lifting competition, you don’t truly ever have to test a one-rep max. Increases in strength gains are great but testing those with a big one-rep max day can be taxing and detrimental to the program as a whole.

Let’s take the example of an athlete who wants to improve their squat from 315 to 405 lbs, ultimately helping them run faster and jump higher. If they constantly test their one-rep max every week, they will gas themselves out to the point that it could take three to four days of recovery before they can do any meaningful form of lower body training again at high intensity. This comes back to expression versus development; plus the fact that most novice lifters will throw technique out the window if all they ever do is try to test their one-rep max. So now they’re decreasing the number of meaningful training days they can complete and limiting the number of high quality reps in their program. That’s a recipe for zero jump and sprint gains at the end of the offseason.

Most novice lifters will throw technique out the window if all they ever do is try to test their one-rep max, says @billmills. Share on X

Rather, I would suggest high-effort reps, even if they are heavy sets of one to three reps. Always try to move the bar as fast as possible. Never miss a rep and add weight week in and week out. If you have a bar speed sensor, you can test the expression of each rep and ultimately ensure high quality. That’s a recipe for success!

What Are Some Common Forms of Expression?

These are commonly found in the sports performance realm. I’ll break them down between ways they can be a “smart” or a “not so smart” decision depending on how they’re used. It should be noted that these are generalizations. Everyone will have their own unique way of using the following scenarios. Just make sure of the best fit for your program.

One-Rep Max Testing: Most commonly used in compound lifts such as the squat, bench press, deadlift, and other barbell-based lifting movements (Olympic lifts, etc.).

Smart:

• Tested at the middle and end of the offseason.
• Tested after months of consistent training, ensuring perfect form and likely a large increase in performance from when they started.
• Great way to build camaraderie and “buy-in” to training.

Not so smart:

• Tested too frequently, not allowing for enough time spent training to actually increase strength.
• Allowing for sub-par form with the movement.
• Testing in an unsafe setting without spotters, catch-pins, etc.

Key Performance Indicator Testing: These are tests that reflect the power needs found in the sport. For example, a baseball outfielder must be able to accelerate quickly in a sprint and develop rotational power at very high speeds. Some good key performance indicators for this outfielder could be a rotational medicine ball throw for velocity (measuring rotational power), a 30 yd dash (measuring sprint acceleration), and a medicine ball chest pass for distance (measuring upper body pressing power at high speeds). Those measures should go up as a result of all the training done in the program.

Smart:

• Tested once every few weeks to ensure the program is pushing the athletes in the right direction.
• Tested in a competition setting, ensuring that athletes push each other.
• Put these numbers on a leaderboard! Exercises like jumps, sprints, and medicine ball throw velocities belong on the board up there with weightlifting one-rep maxes—it shows what tests correlate best with the sport!

Not so smart:

• Only using the KPI tests in your training, neglecting other important areas.
• Equating a KPI with on-field performance. (Example: “I throw this medicine ball 40 mph, that means I throw a baseball 90 mph, so I don’t have to train throwing a baseball”…it doesn’t work like that!)
• Testing in ill-timed or fatigued conditions. If an athlete just played four games in four days, they probably aren’t ready to test!

Video 5. Once coaches identify their training KPIs, they should track and test every few weeks to make sure their athletes are progressing in the right direction.

What Are Some Common Forms of Development?

These are some ways that you can really focus on development in training. It really comes down to knowing the athlete’s needs best. So in this segment, I’m going to break it down to “If they need more strength” or “If they need more velocity.” Those categories are a simple way to break it down, but understand that a healthy mix of all training types (high speed, heavy load, etc.) should all fit in a program to see the best gains possible.

A healthy mix of all training types (high speed, heavy load, etc.) should all fit in a program to see the best gains possible, says @billmills. Share on X

High Quality Weight Room Reps: Showing up to your workout is half the battle. High quality reps are where the battle is won!

If you need more strength:

• Focus on perfect technique on each rep. Why? When we change technique in an exercise, we change the level of recruitment for the intended muscles. For example, with a dumbbell row,⁴ you want to focus on the muscle groups in the rear shoulder and upper back driving the movement. Too many kids will start the row by extending the hips and yanking the chest upwards, taking away from the effectiveness of the exercise!
• Add weight or reps each week. Progressive overload is crucial to increasing muscle size and maximal force production.
• Heavy sets of five reps work great for a majority of compound lifts. I typically don’t recommend sets with much higher reps than that, as fatigue during the set can take away from the quality of rep.

If you need more speed:

• Use a bar speed sensor if possible. Know what ranges you should be working in to achieve your goals. This also ensures that intent is as high as it can be on every rep.
• Keep bar speeds⁵ from falling too much. For example, if you’re working with a heavy set of three reps and your bar speed is 0.5 m/s, your bar speed should never fall below 0.4 m/s. If you do dip below that, you’re likely running more towards fatigue and further away from power development.

Sprinting, Plyometrics, and Other High-Speed Forms of Training: As I’ve talked about previously, there are some athletes who may have a greater need for these forms of training than others. Regardless, all athletes will likely see some positives come about from these styles of training—just make sure it fits well with the entirety of the program.

If you need more strength:

• Program a few sets of these after a warm up and prior to weightlifting. This can create a great potentiating⁶ effect, helping athletes move some serious weight afterwards. For example, three sets of four to five max-effort jumps can get athletes ready to squat and deadlift a house!
• Do not mix conditioning with speed development! The goal here is not to gas athletes out, as that could run them into fatigue—so much that it will take away from their ability to make progress in the weight room.
• Don’t be afraid to add a little bit of resistance to their high-speed work. I have found that resisted sprints, heavier med ball slams, and chest passes work best with force-deficient athletes. Why? They need to be able to apply more force to their movements. More load should create adaptations leading to more force.

If you need more velocity:

• Measure performance on every rep. Time your sprints, measure jump height, etc. Why? This is the best way to ensure low fatigue and increased performance over time.
• Tailor your speed work to your biggest needs. For example, if you know you have great top speed, but relatively poor acceleration capabilities, you may want to increase volume of shorter sprints and improve performance in those.
• Lighten the load if needed. Assisted jumps, lightweight medicine ball throws, etc. can increase the speed of the movement. This is ultimately the missing factor—applying more velocity to their movements.

Tying It All Together

Always focus on development first. Use key performance indicators as a compass for where your training needs to push, but it is not a map—those KPIs can be a huge help and a great way to build camaraderie. Ultimately, you must always push for high quality reps in every movement. That’s what makes the difference at the end of the program!

Always focus on development first, says @billmills. Share on X

If you haven’t guessed yet, my personal area of expertise is in rotational power sports such as baseball and javelin. Medicine ball throws, jumps, and sprints are all great KPIs for baseball players, golfers, and javelin throwers. I recommend testing every two to three weeks to see that they are improving as a result of training. Those movements can produce greater adaptations with those who are already quite strong and profile as velocity-deficient. Therefore, they really should only be included frequently with those types of athletes. Athletes who are beginners or are more force-deficient should train against heavier resistances. They should aim to increase maximal force production and that will ultimately improve their performance with higher velocities!

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References & Supplemental Media

1. Laby, D.M., Kirschen, D.G., Govindarajulu, U., and DeLand, P. “The Hand-eye Coordination of Professional Baseball Players: The Relationship to Batting.” Optometry and Vision Science, 2018.

2. Miyaguchi, K. and Demura, S. “Relationship between upper-body strength and bat swing speed in high-school baseball players.” J Strength Cond Res. 2012 Jul;26(7):1786-91. doi: 10.1519/JSC.0b013e318236d126. PMID: 21921820.

3. Bill Miller, Instagram, 7/14/2020.

4. Bill Miller, Instagram, 6/23/2021.

5. Rodríguez-Rosell, D., Yáñez-García, J.M., Mora-Custodio, R., Pareja-Blanco, F., Ravelo-García, A.G., Ribas-Serna J., and González-Badillo, J.J. “Velocity-based resistance training: impact of velocity loss in the set on neuromuscular performance and hormonal response.” Appl Physiol Nutr Metab. 2020 Aug;45(8):817-828. doi: 10.1139/apnm-2019-0829. Epub 2020 Feb 4. PMID: 32017598.

6. Bill Miller, Instagram, 10/7/2020.