Exhausting stretch-shortening cycle (SSC) exercise causes greater impairment in SSC performance than in pure concentric performance

The purpose of the present study was to investigate the fatigue effect of repeated exhaustive stretch-shortening cycle (SSC) exercise on concentric muscle function. Ten healthy male subjects performed SSC exercise [92 (30) jumps] on a special sledge apparatus. Exhaustion occurred on average within 3 min. A squat jump (SJ) test utilizing a concentric-only action was performed immediately before and after the SSC exercise, and then 10 min, 20 min, 2 days and 4 days later. In addition, a drop jump (DJ) test using an SSC was also performed immediately before and 20 min after the SSC exercise, and 2 days and 4 days later. During jump tests, lower limb joint moment, power, and work contributions were analyzed by using the kinetic and kinematic data. The fatigue exercise was characterized by a relatively high blood lactate concentration [7.2 (0.8) mmol x l(-1)] and a 2-day delayed increase in serum creatine kinase activity [486 (300) U x l(-1)]. SJ performance decreased markedly immediately after the SSC exercise (P