Receipts: The Research Behind My Claims on The Feed The Cats Podcast, and Where I was Wrong
I recently sat down for a podcast with Tony Hollar where we talked about my book, his book, and the specialized skill of teaching speed. I made a number of claims during our conversation and here is an audit of the main ones with the citations to back them up.
I also include a mistake I made! So read on for more details.
You can also watch/listen to the podcast here:
https://youtu.be/zTpRrvMYNGo?si=TMhB1EXhMGO22i0I
Claim 1: Sprinting is the skill most associated with goals being scored in soccer.
The research backs this up…..repeatedly.
The cornerstone study here is Faude, Koch, and Meyer (2012), who analyzed video of 360 goals across the second half of the 2007/08 Bundesliga season. Their finding: 83% of goals were preceded by at least one powerful action, and straight sprinting was the most frequent action for both scoring players (45% of goals) and assisting players (38% of goals). Straight sprints outranked jumps, rotations, and change-of-direction sprints by a wide margin.
This isn't a one-off finding. A 2025 follow-up analysis by Daly et al. examined 2,995 actions preceding goals across the last six men's and women's FIFA World Cups (2014–2023) and confirmed it: linear advancing movements (≈41%), particularly sprinting, were the most prevalent actions leading to goals, followed by deceleration (≈22%) and turns (≈19%). The pattern held across sex, player role, and tournament cycle.
Citations:
- Faude, O., Koch, T., & Meyer, T. (2012). Straight sprinting is the most frequent action in goal situations in professional football. Journal of Sports Sciences, 30(7), 625–631.
- Daly, E., et al. (2025). Sprints, decelerations and turns most commonly precede goals in soccer: Analysis of 6 FIFA World Cups. European Journal of Sport Science.
Claim 2 (my error): Improper sprinting form leads to a roughly 31% increased likelihood of hamstring injury.
Note: When I went back to the literature, the most directly applicable number I found was 33%, not 31%! I want to be honest about that. But, this only further makes my point: sprint mechanics are a measurable, prospective predictor of hamstring injury risk.
Kalema et al. (2024) conducted a six-month prospective cohort study of 126 elite male footballers from eight English football league clubs. They filmed maximum-velocity sprinting at 240 fps and scored each athlete using the Sprint Mechanics Assessment Score (S-MAS), a validated qualitative tool. The finding: every one-point increase in S-MAS corresponded to a 33% increase in the risk of a new sprint-related hamstring strain injury (adjusted incidence rate ratio: 1.33, 95% CI: 1.01 to 1.76), even after adjusting for age and prior injury.
This was the first study to demonstrate a prospective association between sprint kinematics and future hamstring injury in elite footballers; meaning the mechanics came first, the injury came later. Specific technical deficits like anterior pelvic tilt and reduced hip extension velocity have also been flagged as predictors of hamstring injuries during the late swing phase, when hamstring loading peaks.
Citations:
- Kalema, R. N., et al. (2024). Sprint running mechanics are associated with hamstring strain injury: a 6-month prospective cohort study of 126 elite male footballers. British Journal of Sports Medicine.
- Edouard, P., et al. — research on anterior pelvic tilt and hip extension velocity as predictors of HSI during late swing.
Claim 3: Eyes being down during running shortens stride length.
This is supported through two converging lines of evidence: trunk/head posture and stride mechanics.
When the eyes drop, the head and trunk follow. The downstream effects on stride length are measurable. Warrener et al. (2021), in a study at the University of Colorado Denver, manipulated trunk flexion in runners and found that greater forward lean significantly decreased average stride length by 13 cm and increased stride frequency — the opposite of what the researchers had hypothesized. Greater trunk flexion also impacted joint movements and ground reaction forces.
More direct evidence comes from clinical gait research. A 3D motion analysis study of patients with dropped head syndrome (Nakajima et al., 2021), where chronic neck flexion forces a downward gaze, found that stride length and peak hip-joint extension angle were significantly shorter and smaller compared to healthy controls. When the head drops and gaze goes down, hip extension is restricted, and stride length follows.
The mechanism makes biomechanical sense if you think about it. Looking down breaks the neutral cervical spine position, drives the chest forward, restricts hip extension on the back-side of the stride, and shortens the aerial phase. The result is a shorter stride.
Citations:
- Warrener, A., et al. (2021). The effect of trunk flexion angle on lower limb mechanics during running. (CU Denver research published in Human Movement Science.)
- Nakajima, T., et al. (2021). Dynamic alignment changes during level walking in patients with dropped head syndrome. Scientific Reports, 11.
- Donà, G., et al. — research on horizontal gaze stability as a kinematic feature associated with faster sprint velocities.
Claim 4: The forces on the body during sprinting are not even close to what athletes experience in the weight room.
This is one of the most misunderstood realities in sport science. The peak forces are similar, but the time available to produce them is completely different. That's why a heavy back squat cannot substitute for sprint exposure!
Here's what the research shows:
Ground contact time during sprinting is 80–100 milliseconds. Less than the blink of an eye. Compare that to a 1RM back squat, which takes 2–3 seconds to complete the concentric phase. The athlete has 20–30x more time under load in the weight room than they do on a single sprint contact.
Vertical ground reaction forces during sprinting reach 3–5x body weight per contact, applied in under a tenth of a second. That's a rate of force development the weight room simply cannot replicate. Tillin et al. (2013) showed that early-phase squat rate of force development (≤100 ms) correlated with 5–20 m sprint acceleration (r = −0.54 to −0.63) — but the same study found that late-phasesquat RFD (>100 ms) correlated more strongly with jumping than with sprinting. The slower the movement, the less it transfers to sprint contacts.
Aagaard, Maffiuletti, and others have shown that even the strongest athletes cannot reach their maximal force output within a 100-millisecond window. A massive back squat tells you about peak force at a slow velocity. Sprinting tells you about how much force you can produce in the time it takes the ball of your foot to touch and leave the ground. These are different qualities, governed by different neuromuscular adaptations.
This is why sprint exposure is non-negotiable. You cannot lift your way to fast contacts.
Citations:
- Tillin, N. A., et al. (2013). Identification of contraction phase-specific neuromuscular adaptations to short-term explosive-type and maximal-strength resistance training. European Journal of Applied Physiology.
- Maffiuletti, N. A., et al. (2016). Rate of force development: physiological and methodological considerations. European Journal of Applied Physiology.
- Weyand, P. G., et al. (2000). Faster top running speeds are achieved with greater ground forces not more rapid leg movements. Journal of Applied Physiology.
- Kalkhoven, J. T., et al. — work on stretch-shortening cycle duration and RFD specificity.
Why this matters
Sprinting is the most decisive skill in the most-played sports on earth.
- How an athlete sprints (their mechanics) is a measurable, prospective predictor of injury.
- Posture, including where the eyes go, changes stride mechanics in real time.
- The forces and time constraints of sprinting are not replicated in the weight room.
If sprinting is this important, this trainable, and this specific, then teaching it well is one of the highest-leverage things a coach can do. Breaking the Speed Barrier and the GET F.A.S.T. certification aim do equip ALL coaches to be able to do just that.
P.S - If you are into this kind of stuff, my book has 76 unique citations that aim to substantiate all the claims, ideas, and recommendation we make to help you make your athletes faster and safer.
You can get that here: