Nearly every speed coach uses resisted speed. I have used sleds for years, ranging from tires all the way to custom devices and state of the art resistance machines. I’ve learned that, if you want to get the most out of sled training, you need to step back and see the big picture before zooming into coaching and loading resisted sprints. This article covers the nuances of sled training, and I share my experience trying to follow best practices and popular research. As you’ll see, this means more than just adding another plate to the sled.
Each year the same debates resurface. How heavy should we load a sled to see results in sports performance and which methods work best? I’ve talked about sleds several times and shared alternative options to using body weight load percentages when training. In addition to asking the tough questions about heavy sled pushing, I discussed the limitations of force-velocity concepts in detail. The truth is, when we design workouts, the big disconnect between the research and application widens.
Recently, a few potentiation studies indicated that heavy sleds might help with non-resisted sprints afterward, which created even more confusion about how heavy to load a sled for general training.
Mistake 1. Replicating Research Workouts
My favorite learning opportunities come from reading about the excellent workouts researched by sport scientists collaborating with teams. Next to our own training records, studies looking into actual training programs let us see how variables mingle. Unfortunately they don’t always include the factors that may interfere when we try to transplant those elements into our own programs.
For example, how many times have we seen sled training studies that don’t include an aggressive weight training program that we would see at a college or organized high school? How many of the sled programs use plyometrics or volumes that are typical of your program? We can still benefit from studies that are unrealistic, however. If isolated variables don’t do much in an 8-week study with all the eggs in one basket, how can they do anything exciting when they’re part of a holistic program?
A healthy way to extract the right message from the research is to look at the results of the study and avoid the conclusion. Coaches should start with the study design and then look at the discussion, which may hint about why a study failed to get results of similar studies or offer cautions regarding why the study may not be relevant to your situation.
Good researchers are always careful with their findings. They concentrate more on discovering patterns and factors that contribute to performance rather than trying to innovate training methods. Although many good coaches have unpublished “experiments” that precede the research, peer review is still necessary. Read the studies but don’t expect the same results. Our programs usually include factors that don’t jive with the population studied in the experiment.
Mistake 2. Poor Profiling of Your Athletes’ Trainability
One of the few times I’ve had a eureka moment was when I witnessed a high school training session on the first day of practice. The coach did not do a movement screen, he did a trainability assessment. And it was awesome. Instead of performing mobility tests or strange exercises, he simply asked for warm-ups of training elements he found were fundamental and important.
I loved this because he was making the point that an athlete’s training age was more important than any other variable in his program. His definition of training age focused on growth and progress derived from training, not how many years one showed up to practice. We don’t need to do a repetition max of pull-ups if an athlete can do 8 perfect reps. We know they did something productive. Even an athlete who’s familiar with exercise names and can perform them with skill is golden; jump testing without knowing an athlete’s fluency with plyometrics does not help much when training them later.
If I were to rewrite the movement screen article, I would elaborate on the spectrum of an athlete’s competency. If an athlete has a poor profile or time in a 30-meter sprint, the most common approach is to check if the qualities of velocity force were off, and I used to believe this was correct. Now trainability evaluation sheds more light on why they athletes trend well or poorly on speed tests.Evaluating #trainability sheds light on why athletes trend well or poorly on speed tests, says @spikesonly. Click To Tweet
If an athlete is not experienced or proficient in the weight room, heavy sleds may work immediately. But when they want to advance, they won’t have the needed skill sets. Direct methods like resisted sprints are great when time is precious. For true long-term development, however, we must make the athlete skilled in the weight room and implement training on the field. The athlete will not only catch up and pass the linear thinking options, but they’ll also have a higher ceiling.
My favorite example of this occurred 15 years ago when another coach recommended maximal sprinting for my soccer athletes to improve acceleration. He knew that raising the ceiling early would help us prime specific short speed with sled protocols. Look at the research from Ken Clark—it’s very hard to find poor accelerators when top speed is in place. Trainability isn’t just familiarization of workouts specific to the sporting game, it’s about making the athletes highly robust and adaptable.
Mistake 3. Loading Sleds too Light or too Heavy
Years ago I outlined the three big variables with sleds: the lean, length, and load of the training. I used to load sleds heavy since it produced near immediate results. And I didn’t understand why athletes would sprint with a 25-pound plate when they could simply sprint unloaded. Conversely, when I saw athletes pushing heavy sleds, I questioned why they didn’t go to the weight room and do a reverse leg press?Heavy sled marching and pushing compromise the long-term adaptations from running fast, says @spikesonly. Click To Tweet
Heavy sled marching and pushing compromise the ceiling and long-term adaptations from running fast. If you’re not exposing athletes to enough high velocities, the benefits of specific strength eventually become noise. Like all variables, as the athlete develops, their genetic ceiling eventually retards development. Plateaus from systematic improvement over years is acceptable, but it’s a different story if you’re not using the right training modality correctly.
- If you are pushing a heavy sled for speed development form and an increase in specific leg strength, are you complimenting your program with maximal speed development?
- If you are using a super light sled, make sure it’s for long repetitions and to get more speed exposure when the risk of injuries might be higher.
Derek Hansen has discussed some of the pitfalls of pushing a sled. For me, the issue is the difference between the ergonomics of pulling versus pushing. Pulling a sled, even if it’s too heavy, removes the common problem of hyperextension of the back and lack of arm drive that’s important to teach. Youth athletes tend to push sleds to get stronger, but the same athletes need coordination. Decreasing the load may get some connection between the upper and lower body.
Arms are considered reflexive responses to sprinting, but how many times do we see bad arm action interfere with good lower body movement? Hoping the body falls into place with all parts of development is lazy. Guide the process with activities that are athletic and still overload the body.
Mistake 4. Using Potentiation Improperly in Training
My prime problem with potentiation with sleds is the workflow. A heavy sled for one athlete maybe a too light for another due to the nature of individualization. Since the common sled models are similar enough to allow coaches to adopt a similar loading strategy, most studies use body weight or body mass percentages to prescribe training. If you use potentiation to improve unloaded runs, be careful with how much volume you use.
Like repeated sprinting tests, if we don’t have a baseline unloaded repetition, how do we compare the effectiveness of the potentiation and manage fatigue? Two studies looked at potentiation with loads above 120% of body mass, and both failed to accomplish anything while the studies using 75% showed promise. This is the only time I like going heavier than 30%-50% of an athlete’s weight.We need an unloaded baseline rep to compare the effectiveness of potentiation and manage fatigue, says @spikesonly. Click To Tweet
While most coaches will not convert to advanced load prescription and stay with percentages of body mass, some are moving to time because they like splits. Those who use splits are moving towards sensors, so I expect them to convert ballpark suggestions of percentages of mass to more laser targeted loading schemes.
Rest periods that are too long are also not practical. If an athlete uses 12 minutes per rep, they tend to cool off and don’t sustain focus. Five reps that take an hour of time is not realistic, and even 45 minutes is not ideal when the range of the potentiation window is closer to 4-5 minutes. Testing both the loaded run and undressed sprint will help cut off the workout when the reps are not hitting the baseline.
Contrast training may work because of its potentiation benefits, but it’s likely that athlete engagement encourages a better repetition due to motivation. I don’t know how one would create a study that blinds the loading, but more research on contrast training with potentiation is needed to see how a workout can be better constructed rather than how one single repetition is better.
Implementation is easy. After athletes perform 2-3 sprints, they can do contrast work by swapping and staggering unloaded reps and potentiating sprints. I haven’t seen any specific pattern that jumps out as a leading solution. I have alternated potentiation reps with unloaded reps, created waves of loaded and unloaded sets, and even tried adding a weight exercise.
Contrast training is still very embryonic in the research, so using timing and knowledge of the sled’s friction may be a way for coaches to design better workouts. Regardless of the session design, we can clearly see fatigue and potentiation with electronic timing so be sure to get baselines.
Mistake 5. Budgeting Poorly and Knowing When to Buy and When to Build
Several programs do amazingly well without a budget. Some teams are so cash-starved that they hold bake sells to have uniforms and bus transportation. Sleds may not be an option. Even tires from a junkyard need to have storage space—something people take for granted when they have a gym.
An elite team may have the resources for a resisted sprinting device, but even sleds from a performance catalog may not be possible. Having 5-8 sleds may cost a thousand dollars, and building your own sometimes is not allowed because of possible lawsuits. As you can see, the average high school coach can be at a loss about what to do when even the weights for sleds are a financial burden.
If you’re not allowed to use sleds because of complaints about surface wear and tear, an Exer-Genie lasts years and has no weights that require a budget. While sharing weights with others in the weight room is smart on paper, other teams usually complain when they come to a facility and aren’t able to use the weights because field training is hogging them. We budget $50 a year per device so we can buy new ones and replace old ones, and some programs have models that are 20 years old!
If you build equipment, do it right. You are responsible for what you buy and what you build. If someone gets hurt, you may be found negligent if you make something cheap and flimsy. I do recommend railings for sleds, and make the tubing or surface round and wide so the grass or turf isn’t beat up too much. Parachutes are not great solutions for acceleration; they’re more effective as the athlete increases speed, and they tend to break down. The best option might be hills, which can be used with groups and can cost nothing, but access to a great incline isn’t common enough to list as a primary option.
Mistake 6: Wasting the Most Important Resource—Time
Time is our enemy. If you don’t use your time well to improve, don’t worry about what your competition is doing. When I see sleds used in training, I see too many adjustments of loads and problems swapping out harnesses. Similar to the discussion about budgeting, time is a resource you must use wisely.
If you have a typical team of 25 athletes, say a varsity soccer team, buy waist harnesses, not more sleds. Label each one with a number and give a belt to each athlete. Using a clip carabiner, attach the sled cord to the athlete instead of swapping out belts. Based on common intervals, say 3 minutes, up to 6 athletes can share a sled. This means 4-5 sleds can do the trick. I prefer more than that but would rather have better sleds than more of them.
Chains are good alternatives for some programs that have indoor space, but teams with groundskeepers complain about the grass getting beat up when athletes use chains outside.
Video 1. Chain sprints are options for athletes who have access to the right surface and adjustable loads of 10-30 kilograms. Without any instruction at all, most athletes can accelerate with good extension after a few steps by having some resistance.
Besides the hassle of sharing sleds, loading them and knowing the total amount of friction can be a struggle. Sled friction can change based on an array of variables, including weather and changes to the sled itself over time. Don’t get discouraged, simply use electronic timing and a hand scale (suitcase scale) to see how the load changes or stays the same. Most coaches will not have to do this more than a few times the first year; switching grass fields changed the load by over 10% for us!
High school practice fields are always slower than varsity game fields, so take note of the results from each field. Even a fresh cut will change the numbers a bit, so record that when testing. All of this may seem like an unnecessary headache, but nothing is more frustrating than wasting time. Get the burden of evaluating equipment, fields, and other factors out of the way early so you’re not spending hours confused by your training program when athletes are not responding the way they should.
Mistake 7: Chasing Utopian Loads and Overzealous Optimization Strategies
Perhaps the most common question is how heavy to load a sled, which has led to feuds involving sensitive egos and very complicated investigations that simply overthink the nature of training. The truth is this: the loads don’t matter as much as the entire program. Coaches have produced world-class athletes with ultra-light sleds, and some programs have helped create Olympians with loads much heavier than half of their body weight. We’ve seen the evolution of the 10% rule to very precise methods to prescribe ideal loads.
With resisted sprinting, the primary concern is that one variable of one modality is extremely narrow in scope and has little impact on improving an athlete in all areas of speed. While better maximal strength will improve the first few steps by helping a sprinter technically in all events, a sled load and posture are static. Systemically a resisted run will help an athlete accelerate better over short distances, but it influences the segments that are earlier in the run.Sled loading helps acceleration but not global speed. Global speed helps acceleration capacity, says @spikesonly. Click To Tweet
The takeaway is that sled loading helps acceleration but not global speed. Conversely, global speed helps acceleration capacity, especially with a good jump and strength program. I’m not suggesting we don’t use sleds. But if you’re a coach with a comprehensive program, sled variables start to have decreased impact, and overzealous optimization strategies look foolish.
A sane approach is to create a great sled program, not a perfect one. It’s better to manage the volume of loads of resisted speed and all elements during the week than to worry about reaching peak force or peak power. Sled loads are about hitting the transition areas of acceleration that are harder to develop, not about horizontal force scores, which have conflicting research.
Simply leaning with a load that allows a sprinter to maintain an aggressive angle is enough to overcome forces horizontally. Unloaded runs result in postures that become more vertical and cause force analysis of foot strike to appear less effective. Stride effectiveness is about the best resulting composite of lateral, horizontal, and vertical forces that create the highest speed. Still, use the research available to draw smart conclusions about which load is likely to achieve the response you want.
How to Load a Sled
With sleds, the best load is the right load, and what is right is usually lands close to speed work and at the lowest form of strength.
- If an athlete is working acceleration, the load should be light enough to allow them to accelerate the entire distance, or close to it.
- If the second step is as slow as the first one, the load is too heavy.
- Heavier loads that taper off earlier are fine only if other areas are developed and no other options for improvement are realistic.
- If an athlete is gifted in the weight room, go lighter.
- If strength training isn’t historically strong but the athlete has great speed, go heavier but don’t ignore the athlete’s long-term
Loaded sprints appear great. But when training time is decreased, access to maximal effort sprints is rare, so lighter may be a reasonable way to manage underprepared athletes who compete too much. I would rather have ultra-light sprints and good weight room training than a heavier load on a sled. It’s important to expose athletes to fast contractions and long-term weight training.
Mistake 8: Not Preparing the Ankle Properly
The main advantage of sleds as a strength exercise is loading the ankle, specifically the propulsive muscles. Squatting is very similar to sled pushing, using the quads and hamstrings, but when pushing a heavy prowler or running with a loaded sled, the gastrocnemius is highly recruited. Most athletes respond to heavy sled training because of the specific benefits of forefoot loading and pushing back. This type of strength will not come from any static lift like squats or lunges. While the lower leg does have some stabilization during traditional lifts, the recruitment is far less than running, jumping, and resisted sprints.
Video 2. While slightly staged for educational purposes, this video shows how many athletes have excessive heel drop because their plantar flexors are simply not prepared for heavy sleds. A good foot strike maintains a boot-like position when the shoe hits the ground.
If coaches were to address the ankle complex better, would sleds have the same impact? I tend to think that the more holistic a program, the less magnitude of effect a modality will have in training. I also tend to see poor stiffness and more “flat tire” running with heavy sled work, especially heavy pushes that resemble someone trying to build a pyramid instead of running fast. When you use a heavy sled, only load it as heavy as the ankle can handle since excessive dorsiflexion is bad for the Achilles and does not teach anything intelligent regarding motor skills.
A combination of specific calf work and plyometrics won’t take a lot of time and energy from the weight room and field training, and it will pay off later. You don’t need a lot of lower leg training, just enough to support the resisted sprinting so the ankle isn’t a weak link. I’ve learned the hard way that using sleds to prepare for the specific needs of ankle stiffness isn’t as effective as plyos and simple plantar eccentric work. Also, sleds tend to reveal more than they prepare in this area.
Construct Sled Workouts that Work
Great sled training hits the spot when the speed is fast enough to resemble the qualities of sprinting and the overload is enough to make a difference in addition to the weight room. Knowing how unloaded sprinting can help a program and which weight room workouts will complement speed development leaves the right resources for sled sprinting. If sleds become specific strength exercises and force each step to accelerate, then it’s time to rethink the program entirely.
Some sports need athletes to maul each other, such as rugby and American football, and sleds can offer a great way to help with contact situations. But for speed, think lighter and smarter.
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