Comparisons of exercise-induced muscle damage after two closely scheduled sprinting exercises

BACKGROUND: Individuals may suffer from repeated sprints-induced muscle damage, which could lead to a prolonged recovery period, thereby influencing subsequent closely-scheduled training or competitions. OBJECTIVE: To examine whether an initial muscle-damaging sprint exercise could confer a protective effect against muscle damage induced by the subsequent identical exercise performed four days later. METHODS: Fourteen physically-active men completed two sprinting bouts (15 sets of 30-m maximal sprints) with 4 days apart. Before, 24, 48, and 72 hours after both bouts, muscle damage markers were measured. In addition, time trial, along with the peak heart rate (HR) and rating of perceived exertion (RPE) during each sprint set were also recorded. RESULTS: Comparing to the initial bout, less muscle soreness and faster recoveries of the knee flexion eccentric peak torque and angle of peak torque were found following the second bout. In addition, the time trial and HR for each sprint set were not different between the two bouts, but the average RPE was less during the second bout (p = 0.013). CONCLUSIONS: The protective effect from the exposure to the initial sprint was evident. Thus, repeated exposures to the sport-specific sprints can positively influence the symptoms of muscle damage without influencing the sprinting performance.