What did the study look at?

The primary objective was to evaluate the effectiveness of resisted sled sprtint (RSS) training compared with unresisted sprint (URS) training, and the differential effects of sled load on RSS training outcomes.

Why is it important?

Pulling a sled is a crucial component of acceleration training for several reasons. Firstly, it enhances an athlete's ability to generate explosive power and strength, which are fundamental for quick acceleration in sports like sprinting, football, and track and field events. The resistance provided by the sled forces the athlete to overcome inertia and drive forward with maximal force, thereby improving their starting speed.

Additionally, sled training helps develop proper sprinting mechanics, including a powerful leg drive and a forward body lean, which are essential for efficient acceleration. Moreover, it can be tailored to mimic the specific demands of an athlete's sport, allowing for sport-specific training that directly translates to improved on-field performance. Overall, pulling a sled is an invaluable tool in the arsenal of acceleration training, helping athletes unlock their full potential in terms of explosive speed and agility.

How did they do it?

A total of 11 studies fulfilled the eligibility criteria. Sled loads were prescribed either as a percentage of body mass (%BM), a targeted reduction in velocity compared with unresisted sprint velocity (%V _dec) or as an absolute load (kg).

What were the results?

RSS training with ‘light’ (<10 %BM or <10 %V _dec) loads provide ‘small’ decrements in acceleration (−1.5 %, ES = 0.50) to ‘moderate’ improvements in maximal sprint velocity (2.4 %, ES = 0.80) in sprint-trained individuals. ‘Moderate’ (10–19.9 %BM or 10–14.9 %V _dec) to ‘very heavy’ (>30 %BM or >30 %V _dec) sled loads provide ‘trivial’ to ‘extremely large’ improvements in acceleration performance (0.5–9.1 %, ES = 0.14–4.00) in strength-trained or team sport individuals.

Whether RSS training is more effective than URS training in the improvement of acceleration or maximal sprint velocity remains equivocal.

How should you apply this to training?

RSS training is a novel training method with potential for the improvement of sprint performance, but its performance benefits over URS training remain to be conclusively demonstrated. Between-study comparisons are limited primarily by discrepancies in the training status and phase of the participants, and sled load prescription.

Future work is required to define the optimal load and volume for RSS depending on the specific components of sprint performance to be enhanced.