Korfist and Fichter on Foot Strength and Wave Sprints

Chris Korfist and Dan Fichter joined host Chris Kerr to answer a question Kerr borrowed from Ken Clark: in a winter and spring track season, what single quality changes sprint speed the most? Both coaches landed on foot strength, with Korfist describing how his five to six sub-11 second 100 meter athletes share a rolling, tangential push through the big toe and Fichter framing the body as a Jenga system that has to absorb impact forces from the ground up. The conversation moved into wave sprint protocols on the DynaSpeed, hip flexor research from Japan, and how Fichter trains football players to fall before he trains them to sprint.

Key Takeaways

• Foot strength is the lever: Fichter said athletes who cannot absorb energy through the lower leg will not run fast, and Korfist agreed that his sub-11 second 100m athletes all share a rolling, tangential foot strike off the big toe rather than a piston action.
• Isometrics and the Toe Pro anchor the work: Korfist prescribes 2 to 3 minute isometric holds and said he and Fichter use the Toe Pro quite a bit. Fichter brings the Toe Pro everywhere and adds heel walks for anterior tibialis strength, watching the torso to catch compensations.
• Wave sprints have replaced traditional repeats: Korfist runs an oscillating resistance protocol on the DynaSpeed that switches load every 10 meters, including a 100 meter version, and reports weekly time drops with athletes training the wave once or twice a week.
• Train the fall before the sprint: Fichter opens football sessions with 100 partner-cued reaches in varied vectors, foot positions, and head positions, then runs 5 into 10 yard accelerations. He frames the body as a Jenga system that must stay aligned to transmit force.
• Hip flexor work is back on the table: Korfist cited Japanese research on the role of the hip flexor and rectus femoris in sprint fatigue and said most athletes test weak in the rec fem when assessed in hip flexion rather than in a squat pattern.

Foot Strength as the Non-Negotiable

Asked what quality moves the needle most in a track season, Fichter answered foot strength without hesitation, saying athletes who cannot absorb energy in and through the lower leg will not run fast. Korfist agreed and added that watching his fastest athletes from the side, they all run differently but share the same foot departure: a rolling push through the ball of the big toe with a tangential, slicing contact rather than a vertical piston. Both coaches lean on the Toe Pro and isometric work, with Korfist holding positions for 2 to 3 minutes.

“To change somebody’s speed, I think you have to change the strength of their foot.”, Dan Fichter

The Jenga Model of Impact Forces

Fichter described the body as a human Jenga system where every block must stay aligned for impact forces to be absorbed and redirected. If a hip is out of position, there is no transmission of force, and the system collapses. He tied this to falling: athletes have to practice the act of falling so the nervous system trusts the extreme positions acceleration demands. Coaching foot position biomechanically misses the point if the brain has no faith the body will not bounce off the ground.

“Your body is like a human Jenga system. If you ever see the Jengas, when they get out, if you slide them in, you’re pretty stable.”, Dan Fichter

Wave Sprints on the DynaSpeed

Korfist said his training life is now pre and post 1080 Sprint. His group did one 23 second run and one fly day all season; currently, he said the wave run is so central that everything revolves around that one day a week. The wave sprint oscillates resistance every 10 meters from heavy to light, smoothly enough that the stride is not jerked but obvious enough that athletes feel the load change. He tested 5 meter intervals and found them too disruptive. The group has run the wave out to 100 meters, and Korfist reports weekly time improvements with athletes training the protocol once or twice a week.

“Right now we like the wave run so much that everything revolves around that one day a week.”, Chris Korfist

Training the Fall in Football Off-Season

Fichter opens football sessions with 100 partner-cued reaches before any lifting, varying vectors, foot positions, and head positions every session. From there athletes move outside for 5 into 10 yard accelerations and back inside for low squat jumps to teach ricochet off a stronger foot. The goal is to build proprioceptive awareness of getting the head and torso out in front so the brain permits the deep acceleration angle. Fichter said changing one step in acceleration changes the game.

“Right now with football guys, they’re preparing and learning how to fall in the weight room.”, Dan Fichter

Hip Flexors, Hypoxia, and What Has Stuck Around

Korfist has been chasing Japanese research on the hip flexor and rectus femoris in sprint fatigue, and said most athletes test weak in the rec fem when assessed in hip flexion rather than from a squat pattern. Fichter brought up a recent paper on hypoxic training in team sports, arguing that repeated short sprints already place athletes in a hypoxic state because they are barely breathing during a 20 yard run, which is why stacked accelerations build conditioning without any deliberate breath holding.

“How fast you can bring that leg through and proper recruitment through for that leg swinging in the air.”, Chris Korfist

Data Points and Metrics

Frequently Asked Questions

What is the most important quality to change to improve sprint speed in a track season?

Both Dan Fichter and Chris Korfist pointed to foot strength as the priority. Fichter said if athletes cannot absorb energy in and through the lower leg, they will not run fast, so indoors he prioritizes foot strengthening, isometrics, and acceleration. Korfist agreed and added that his fastest athletes share a common foot departure off the ground: a rolling push through the ball of the big toe with rotation, not a piston up and down. The foot strikes tangentially, slicing into the ground rather than stamping. Without that quality, impact forces cannot be managed and acceleration positions cannot be held.

How do Chris Korfist and Dan Fichter train foot strength?

Both coaches use the Toe Pro and isometric foot holds, with Korfist prescribing 2 to 3 minute isometric durations. Fichter also has athletes walk on their heels to build the anterior tibialis, watching the torso rather than the heels because balance compensations show up immediately. He noted that anterior tibialis muscles often test strong in isolation but weaken instantly under gait due to compensatory patterns. Korfist described ski jump toe pops, a banded drill where athletes lean forward with weight on the middle two toes and bounce down the track with locked knees to build comfort balancing over the toes during forward propulsion.

What is the wave sprint protocol on the 1080 DynaSpeed?

Korfist programs oscillating resistance that changes every 10 meters, alternating heavy to light across the run. The shift is smooth, not jerky, but athletes feel the resistance change and have to push hard, then maintain speed as it releases, then push again as it loads. He tested 5 meter intervals and found them too disruptive. His group ran the protocol out to 100 meters in a recent session. Korfist said he can roughly predict 100 meter times from the output, and his athletes have improved weekly training the wave once or twice a week. Faster athletes weave through the oscillations; slower athletes plow through without adapting.

How does Dan Fichter prepare football players for acceleration?

Fichter trains his football athletes to fall before he trains them to sprint. Sessions begin with 100 partner-cued reaches in varied vectors with changing foot and head positions to build awareness of getting the body out in front. He then runs 5 into 10 yard accelerations outside, paired with low squat jumps in the weight room to teach ricochet off a stronger foot. He frames the body as a human Jenga system: stability comes from aligned blocks so that impact forces can be absorbed and redirected, and a missing block leaves no path to transmit force.

Why does Dan Fichter favor short sprints over altitude training for conditioning?

Fichter cited recent research on hypoxic training in team sports suggesting that altitude exposure followed by sea-level running offers little benefit, while repeated sprint training under breath holding produces real adaptation. He pointed out that in a 20 yard sprint athletes are essentially not breathing, so stacking accelerations creates a hypoxic state that extends speed endurance without ever asking athletes to consciously hold their breath. He referenced Charlie Francis discussing breath patterns in the 100 meter dash and said this is why shorter fly runs and acceleration repeats produce a team sport conditioning effect.

When does Chris Korfist decide his 4×100 and 4×200 relay order?

Korfist starts deciding early in the season and watches several factors. He said he makes sure athletes can handle exchanges and do not panic or take off too early; if his fastest athlete takes off too early, that athlete becomes his starter. He times curve runs out of the blocks and from a fly, and assigns his best curve runners to those legs. This year his lead-off is a six foot three athlete who eats the stagger on the curve and takes pride in giving the rest of the relay a clean race. Korfist also asks his athletes who they trust carrying the stick.