Effects of 12-week free sprint training and speed, agility, and quickness training (SAQT) on reaction time and lower limb muscle activation during crouch start

Abstract

Purpose: This study investigated the effects of speed, agility, and quickness training (SAQT) and free sprint training (FST) on lower limb muscle activation and crouch start reaction time in university students. Methods: Thirty-six participants were randomly assigned to either the SAQT or FST group. Both groups underwent 12 weeks of training (3 sessions/week). Electromyography (EMG) measured muscle activation and crouch start reaction time at pre-, mid-, and post-intervention. A mixed-design two-way ANOVA assessed changes over time. Results: SAQT led to greater improvements in muscle activation, particularly in the rectus femoris and right biceps femoris. Significant increases in right rectus femoris and biceps femoris activation were observed at 12 weeks (241.10 ± 202.92 and 140.25 ± 62.57) compared with pre-test values (127.36 ± 59.03 and 91.36 ± 44.42; p = 0.010 and 0.014). The FST group showed higher right biceps femoris activation after 6 weeks of training (p = 0.012). No significant differences were found in peroneus longus activation or crouch start reaction time between groups or across time points. Conclusion: SAQT effectively enhanced lower limb muscle activation, suggesting benefits for neuromuscular coordination and explosive power development. The lack of improvement in reaction time may be due to participants’ limited crouch start proficiency. Integrating SAQT with skill-based start drills may better improve sprint performance. Future studies should examine trained or professional athletes to further validate these findings.