The aim of this study was to determine whether performing heavy versus light-load squats prior to sprinting would improve running speed. Twelve elite soccer league players (Age, 22.4 1 years; height, 178 5 cm; body mass, 89 12 kg) performed two sets of four repetitions using light (LS=60% of 1RM), moderate (MS=70% of 1RM), or heavy load squats (HS=85% of 1RM) and a control (C) warm-up condition on randomized separating conditions over the course of two weeks. After a 4-minute post-warm up, the subjects completed a timed 40-meter sprint. The results of this study indicated that the running speed had improved significantly (P<0.05) after LS (-1.9%), MS (-1.77%), and HS (-2.98%) warm-ups compared to C. When compared to squat protocols, significant differences were observed between LS (60% of 1RM) and HS (85% of 1RM) only. The data from this study suggest that performing squats prior to sprinting may improve 40-m sprint times. However, in order to induce optimal running speed enhancement, it is necessary to set the intensity of the warm-up protocol with high-dynamic loading intensities (> 80% of 1RM).
