Acceleration Exercises for Athletes, With Cameron Josse

Based on Episode 63 of the Just Fly Performance Podcast, a conversation between host Joel Smith and DeFranco’s Gym sports performance director Cameron Josse.

Ask Cameron Josse for his favorite acceleration exercises and you get an unusually honest answer, one built on a real experiment. As Director of Sports Performance at DeFranco’s Gym, Josse ran his combine-prep football players through a heavy resisted sprint cycle drawn straight from the force-velocity research of JB Morin, Pierre Samozino, and Matt Cross, then reported what actually happened, caveats included. In this conversation he walks through the toolkit that came out of it: max-power sled sprints, a front-side mechanics drill he invented, power skips, flying sprints, and single-leg strength work, and explains what each one is really for.

Key Takeaways

• Heavy resisted sprinting is strength training, not speed training. It stretches the start’s high-force environment across a whole rep.
• Load by velocity, not bodyweight. Josse targets 48 to 52% of each athlete’s max velocity, because friction makes percent-of-bodyweight unreliable.
• His 40 case study improved times, with honest caveats. One to three tenths in four weeks, but plyos, jumps, and unloaded sprints were also in the program.
• The med ball knee punch run fixes front-side mechanics almost without cueing.
• For football players, 20 yards is already top speed. Ken Clark’s combine data shows 96 to 98% of max velocity by 20 yards.

Heavy sleds: strength training for the start

Josse’s resisted sprint block came from reading the research during combine season and deciding to test it. The core idea is what the load does to the start.

Maximum power in an unloaded sprint typically occurs in less than a second, maybe the first three to five meters. What you do with the max power load on the sled is take that snippet of the unloaded sprint and spread it out over longer distances, so your athletes are exposed to that environment for longer.

He is emphatic about how the researchers themselves classify it.

They specifically say it’s not speed training. They refer to it as strength training that’s very specific to the sprinting motion. You’re producing a lot of force per step, because if you can’t produce force, you’re not going anywhere.

Loading is where most coaches go wrong. Rather than the published bodyweight percentages, which depend entirely on surface friction, Josse profiles each athlete and sets the load by speed: the athlete should average 48 to 52% of their max velocity over the rep, auto-regulated up or down after every run. And the results of his four-week experiment came with the caveat he insists on repeating: his clients averaged one to three tenths off their 40 times, but jumps, plyometrics, unloaded sprints, and light contrast sleds were all in the program too. “It’s hard to say definitively that it was because of the heavy sled training,” he says, and neither he nor the researchers would tell anyone to just drag a heavy sled and expect a faster 40.

The technique is built into the sled

One reason Josse rates resisted sprinting so highly for team-sport athletes is that it coaches itself. The environment does the cueing.

The technical aspect is built into the exercise itself. It’s basically like running up a steep hill, and it’s pretty often you’ll see athletes run up a hill pretty well even if they can’t on flat ground. If they’re not doing it properly, they’re just not going to get anywhere with that resistance.

He has watched the load fix feet that externally rotate at push-off and hips that leak force sideways, without a single cue, because the slower speeds give athletes time to feel the problem and self-correct. It is the same self-organization logic he applies to testing: on flying 10s, when athletes ask when to start speeding up, he tells them the time and lets them figure it out. The knowledge of the result teaches better than a running commentary.

Front-side mechanics and the med ball knee punch run

If sleds handle the start, the biggest gap Josse sees in football players is what happens when they should be upright. Drawing on Ken Clark’s research, he argues team-sport athletes know how to drive out but never learn to run tall, and elite sprinters stay front-side dominant from start to finish. His fix is a drill he invented out of frustration.

They take a really light med ball, three to six pounds, and hold it at their belly button. All I tell them is, just sprint, but the only thing you want to think about is trying to punch your quad to the med ball as you run. That’s the only drill I’ve seen where, when they do it, they all have awesome front-side mechanics.

The logic mirrors the weight room: anterior load makes the body organize itself upright, the way a front squat cleans up a squat pattern. A few weeks of the drill, then take the ball away, and the pattern sticks. He pairs it with A-skips for distance and running As, and he saw it transform a linebacker who used to “kick out the back” and stress his hamstrings; once the athlete felt the more efficient pattern, he could not go back.

Why 20 yards is top speed for a football player

Josse has also replaced the 40 as his internal speed test, using flying 10-yard sprints to measure max velocity directly, a number he finds more honest and far less stressful for athletes than a full 40. The deeper insight comes from a Ken Clark analysis of the NFL Combine.

He looked at the acceleration pattern of everyone at the combine, and whether they were a receiver, a defensive back, or a lineman, they all reached 96 to 98% of their max velocity by the 20-yard mark. So technically speaking, 20 yards or more is top speed work for a football player.

That overturns the track-borrowed assumption that top-speed work needs 50 or 60 meters of runway. It also explains why he defends upright max-velocity training for football players against the “my guy never runs that far” objection: kickoffs, kick returns, and chase-down plays all demand it, and raising the velocity ceiling raises every submaximal speed underneath it. As he puts it, if you bench 400 and the other guy benches 200, your 90% is heavier, and speed works the same way.

Power skips and bounding: the propulsion test

Among his supporting exercises, Josse keeps coming back to the simplest ones. Power skips for distance double as training and as a brutally clear diagnostic.

You get 10 total skips and we track how far you go. Some guys think they’re pretty strong in the weight room, but can you apply this force into the ground? One guy could only hit maybe 35, 40 yards in 10 skips, and some of the other guys were well beyond 50. He realized, oh, this is a problem.

Bounding rounds out the progression, extensive first for technique, intensive later for output, because sprinting, in his words, ends up being bounding at a very fast pace. It strengthens the ankle complex and teaches athletes to transmit force from the hip through the ground, which is the whole game in acceleration.

Single-leg strength, from record board to insurance policy

In the weight room, Josse’s acceleration work centers on explosive single-leg lifts done Westside-style for dynamic effort: reverse lunges, step-ups, and split squats, exploding up from a controlled or dead-stop position, with a Tendo unit keeping average velocity above 1.0 meters per second on the stable variations. DeFranco’s even added a “single-leg squat lockout” to the gym record board, a dead-start rear-foot-elevated press-out on one leg. One running back locked out 320 pounds per leg.

It’s kind of like a deadlift, but on one leg. Can I just power through this on my one leg? And just the confidence you can give somebody by that.

For veterans, the purpose changes. His pros migrate away from heavy bilateral lifting to protect spines and hips that already take a beating across an NFL season, and he is refreshingly blunt about what the weight room is for at that level.

You’re taking out an insurance policy to make sure your muscles, your tendons, all your connective tissues are robust. It’s not necessarily going to improve your performance. It’s about keeping your body safe.

Velocity in the weight room, kept simple

Josse’s velocity-based training deliberately avoids complexity. Dynamic-effort day pairs with top-speed day on the field, max-effort day with acceleration day, and the bar-speed rules are two numbers.

On dynamic effort I keep it one meter per second or higher, and I switch the exercise every two weeks. On heavy days I’ve found 80 to 85% corresponds to about 0.55 to 0.65 meters per second. I don’t really use percentage of 1RM anymore. If you’re feeling great, push closer to 0.55; if you’re not, at least give me 0.65 with whatever you can do that day.

Bands and chains let athletes accelerate through the whole rep instead of braking to protect their knees, and his next experiment is replacing some lifts entirely with weighted jumps, so there is no deceleration at all. For coordinatively demanding single-leg lifts he skips the measurement altogether, because clean movement is the goal there, not bar speed. Even his strongest athletes stay challenged this way: the same 500-plus-squat running back chases velocity targets against bands instead of piling plates on his spine.

Frequently asked questions

What are the best acceleration exercises?
Josse’s core toolkit is actual sprinting first, then maximum-power resisted sled sprints, the med ball knee punch run with skips and bounds for mechanics, power skips for distance, flying sprints to raise max velocity, and explosive single-leg strength work in the weight room.

How heavy should a resisted sprint or sled be?
Heavy enough that the athlete averages roughly 48 to 52% of their max velocity over the rep. Josse sets load by measured speed rather than percent of bodyweight, because friction between surfaces makes bodyweight prescriptions unreliable.

Do heavy sleds make you faster?
His four-week case study saw 40-yard dash times improve one to three tenths, but he is careful to note the program also included jumps, plyometrics, and unloaded sprinting, so the sled alone cannot claim the credit. He treats heavy resisted sprinting as acceleration-specific strength work inside a complete speed program, not a shortcut.

What are front-side mechanics?
Keeping the knees punching up and forward in front of the body throughout the sprint, rather than letting the legs cycle out the back. Elite sprinters stay front-side dominant from start to finish, and Josse trains it with his med ball knee punch run, A-skips, and running As.

How should football players test and train top speed?
Josse uses flying 10-yard sprints to measure max velocity directly, which he finds a better indicator of team-sport speed than the 40. Because combine athletes hit 96 to 98% of max velocity by 20 yards, sprints of 20-plus yards already function as top-speed work for football players.

About the authors

Cameron Josse was the Director of Sports Performance at DeFranco’s Gym at the time of this episode, training football players from high school through the NFL, including combine and pro-day preparation. He is known for applying sprint force-velocity research and max-velocity science to team-sport speed development, and his writing on resisted sprint training has appeared on SimpliFaster.

Joel Smith is the host of the Just Fly Performance Podcast and the founder of Just Fly Sports, a former collegiate strength and track and field coach focused on speed, power, and athletic development. Listen to the full episode with Cameron Josse on Just Fly Sports.