Stride or turnover? What separates the faster sprinter

The paper: Nagahara, R. (2023). Normative spatiotemporal and ground reaction force data for female and male sprinting. Journal of Sports Sciences, 41(12), 1240–1249. doi.org/10.1080/02640414.2023.2265641

This study set out to establish what actually changes as a sprinter gets faster. It measured 146 sprinters across a range of abilities over one of the rarest instruments in the sport — a 52-metre runway of force plates — and separated them into performance tiers. The pattern that emerged is a useful one: step length develops early, but the athletes who keep getting faster do so through higher turnover and greater propulsive force.

The study

Forty-four female and 102 male sprinters, spanning club to national level, ran maximal 60 m sprints from blocks. Every step from the start to top speed was recorded on a 54-plate force runway sampling at 1000 Hz, capturing both the spatiotemporal measures — step length, step rate, contact time and flight time — and the ground reaction forces beneath them. Each sex was divided into four tiers by top speed.

Because taller athletes naturally take longer, slower steps, step length and step rate were also expressed as stature-adjusted indices, so that turnover could be compared independently of height.

What they found

Turnover, more than step length, separates the faster sprinters. Once step length is developed it changes little between the higher tiers, whereas step rate keeps climbing. Expressed as stature-adjusted indices — which strip out the effect of height — the step-frequency index rises steadily across the performance levels, while the step-length index is essentially flat, and its differences between tiers were not statistically significant.

Change in each stature-adjusted index across the four male performance tiers (values from the paper’s Table 3, relative to the slowest tier). The step-frequency index climbs steadily and its differences between tiers were statistically significant (ANOVA p < 0.001); the step-length index barely moves, and its differences were not significant (p = 0.061).

That higher turnover comes from shorter ground contact, not from more time in the air. Step rate is the inverse of contact time plus flight time, and only one of the two actually changes. Averaged across the acceleration, ground contact — the paper’s “support time” — shortens markedly with performance level: from roughly 0.124 s to 0.108 s across the male tiers, and 0.132 s to 0.112 s across the female tiers. Flight time barely moves — around 0.10 s for the men and 0.11 s for the women, with no consistent trend. Faster sprinters raise their turnover by spending less time on the ground, not by floating longer between steps.

The gap between tiers is driven by propulsive force, not reduced braking. Read alongside the contact-time finding, this is the crux: the faster sprinters apply more propulsive force in less ground contact — greater force, delivered in a shorter time. It held for both sexes.

At matched performance levels, men and women use different strategies. Women reached comparable levels with shorter ground contacts, longer flight times, and greater force relative to body mass.

Strengths and limitations

Strengths

• Direct force measurement across the entire acceleration — a 52 m force runway is an instrument almost no laboratory possesses.
• A large sample of 146 athletes, both sexes, across four performance tiers each.
• Stature-adjusted indices separate genuine turnover from the simple effect of being tall.

Limitations

• The sample is predominantly sub-elite (mean 100 m bests around 12.55 s for the women and 11.17 s for the men), so the data are normative for club-to-national sprinters, not world class.
• The fastest female tier contains only two athletes; anything drawn from it is indicative at most.
• The design is cross-sectional. It compares different athletes at different levels, so it shows that faster sprinters have higher turnover and greater propulsive force — not that increasing either would make a given athlete faster.
• The data come from a testing session rather than competition, where running speeds may be higher.

Practical takeaways

• Step length develops early; turnover carries an athlete higher. For an already-competent sprinter, step frequency is the more likely lever for further speed — provided step length is not being sacrificed to reach it.
• Higher turnover comes from shorter ground contact, not more flight. Faster sprinters raise step rate by cutting contact time while flight time holds steady, so ground contact is the variable to target — and the aim is to apply more propulsive force in that shorter contact, not simply to leave the ground sooner. Across the tiers it was propulsion, not reduced braking, that separated the fastest.
• Account for height when setting targets. Stature strongly influences step length and rate, so judge an athlete against stature-adjusted references rather than raw group means.
• Track step frequency and contact time over a season. These are the measures that move with performance level, which makes them the ones worth monitoring to confirm an athlete is progressing.