Speed changes following 4 weeks of resisted and overspeed sprints

This summer I trained a D1-bound female soccer athlete whose primary goal was improved speed. We worked together twice per week. One session involved resisted sprints at max power while the other was overspeed sprints at 105-110% max velocity, both utilizing the 1080 Sprint.

I like this combination of training because it covers both ends of the force-velocity spectrum. Sure, the resisted sprints could be heavier to really hammer the force side of the curve, but sprinting at Pmax involves pretty heavy resistance and makes athletes more powerful, which is a critical element of sprint performance.

After just four weeks of training, this athlete had phenomenal results, dropping her 30m sprint time (against 3kg resistance on the 1080) by 0.3s. Detailed sprint data later in this post.

Training protocol

Day 1 was a baseline testing day. We performed a load velocity profiling as well as two 30m sprints, the fastest of which is used as her baseline performance numbers seen here.

Resisted sprints

The load-velocity profile allowed me to quickly understand what resistance would reduce this athletes maximum velocity by 50%, which are the conditions to achieve maximum power in resisted sprints.1

All sprints were 15m and separated by at least 3 minutes rest. The athlete completed four resisted sprint sessions between test dates. Below is a quick summary of each session.

Because the resistance remained the same for each session, power is representative of sprint time. Higher power = lower sprint time. Outside of the second session, which was worse than the first from a numbers perspective, this athlete demonstrated more powerful (faster) sprints with each training session.

Overspeed sprints

Overspeed sprints consisted of a 20m build up to a 20m max speed sprint. Sprints were completed in sets, with one set consisting of two consecutive overspeed sprints followed by one unresisted sprint to encourage transference. Each sprint was separated by at least 4 minutes rest.

Below is a summary of each session.

Data taken from fastest 10m split of each sprint.

Clear upward trends in velocity are present in the data. Perhaps most notably, we see an increase in max velocity from 8.19 m/s in session one to 8.32 m/s in session 4, an increase of 0.13 m/s. Not bad for 3 weeks of training.

Results analysis

As mentioned above, the athlete decreased her 30m sprint time by 0.3s (5.46s to 5.16s) after 4 weeks of training. Below is a breakdown of each 5m sprint of her pre- (before) and post- (after) training sprints.

Table comparing pre- and post-training 30m sprint data.

In the “before” sprint, the athlete’s split times for the final three 5m segments are identical at 0.76s, indicating she essentially did not speed up beyond the 15m mark. Big burst to start, but hit max speed pretty quickly and actually slowed down for the final 5m of the sprint.

By comparison, the post-training 30m sprint shows faster velocities through each 5m segment with the athlete never reaching peak velocity or decelerating. Further, her maximum speed is improved by 0.35 m/s.

What I think is most impressive is the difference in her start. She shaved 0.13s from the first 5m of her acceleration, which set the stage for the increased performance through each subsequent 5m section. The rate of acceleration for the 5-10m and 10-15m segments did not change much, indicating the faster start (first 5m) as the driver of performance improvements in the first half of the sprint. However, increased maximum velocity allowed the athlete to continue accelerating and reach higher speeds in the final half of the sprint, allowing for improved performance from 15-30m.

These results highlight the importance of training maximum velocity and acceleration, even for a 30m sprint. As Ken Clark has noted, NFL combine athletes reach 90% of their top speed by the time they cross the 20 and that the fastest athletes (velocity) had the best times at each split.2

All in all, this athlete had great results. She always showed up with a great attitude and worked her tail off. Hats off to her; she earned every bit of her speed gains.

References

  1. Cross, M. R., Brughelli, M., Samozino, P., Brown, S. R., & Morin, J. B. (2017). Optimal loading for maximizing power during sled-resisted sprinting. International journal of sports physiology and performance, 12(8), 1069-1077.
  2. Clark, K. P., Rieger, R. H., Bruno, R. F., & Stearne, D. J. (2017). “The NFL Combine 40-Yard Dash: How Important is Maximum Velocity?” The Journal of Strength & Conditioning Research.

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