Effects of vest and sled resisted sprint training on sprint performance in young soccer players: a systematic review and meta-analysis.

The aim of the meta-analysis was to determine the effect of resisted sprint training (RST) on sprint performance in young (<20 years) soccer players and to analyze whether the training equipment (sled or vest) and magnitude of the resistive load (above or below 20% of body mass [BM]) influences the long-term adaptations in sprint performance. Resisted sprint training reduced the acceleration phase time [standardized mean difference (SMD) = −0.41], with greater reduction in sprint time occurring in response to applying resistance with a vest (SMD = −0.70) when compared with a sled (SMD = −0.27). Similar reductions were determined for resistive loads <20% (SMD = −0.55) and ≥20% of BM (SMD = −0.31). Full sprint time showed a small reduction after RST (SMD = −0.36), regardless of the training equipment (sled: SMD = −0.44; vest: SMD = −0.26) and resistive load (