Horita T, Komi P V, Nicol C, Kyröläinen H
Neuromuscular Research Centre, Department of Biology of Physical Activity, University of Jyväskylä, Finland.
Eur J Appl Physiol Occup Physiol. 1999 Jan;79(2):160-7. doi: 10.1007/s004210050490.
The purpose of the present study was to investigate the effect of stretch-shortening-cycle-induced muscle damage on the time course of mechanical behaviour in the drop jump. Ten healthy male subjects performed submaximal stretch-shortening cycle (SSC) exercise on a special sledge apparatus. Exhaustion occurred on average within 3 min. A drop jump (DJ) test from a 50-cm height was performed before and immediately after the sledge exercise as well as 2 h, 2 days and 4 days later. The fatigue exercise showed relatively high blood lactate concentration [12.5 (SD 2.6) mmol x l(-1)] and an increase of serum creatine kinase (CK) activity delayed by 2 days [540 (SD 407) U x l(-1)]. The initial decline in the jump performance (before - immediately after) was related negatively to the early recovery in performance (immediately after 2 h) (P < 0.05). The early recovery of the knee joint moment at the end of stretch showed a negative correlation to the delayed decrease in DJ performance (2 h 2 days) (P < 0.01). Thus, the DJ performance showed an initial decline followed by an early recovery and a secondary decline. Both the initial decline and early recovery in the knee joint moment at the end of stretch were related to the corresponding initial (after 2 h) (P < 0.05) and secondary increases (2 h - 2 days) (P < 0.01) in CK. It is suggested that the early recovery as well as the initial decline in the knee joint function could depend on the degree of muscle damage. Delayed decrease in initial stiffness (2 h - 2 days) was negatively related to the corresponding changes in the knee joint angle at touch down in DJ (P < 0.001). These interactions would imply that the decrease in the stiffness regulation and the modulation of the prelanding motor control might be attributable to secondary muscle damage during 2 days after the SSC exercise. Therefore, it may be suggested that the changes in the DJ performance after the exhausting SSC exercise accompany the progress of muscle damage observed by the corresponding increase in serum CK concentration and the corresponding deterioration of stiffness regulation and motor control in DJ.
本研究的目的是调查拉长-缩短周期诱导的肌肉损伤对纵跳力学行为时间进程的影响。10名健康男性受试者在一种特殊的雪橇装置上进行次最大强度的拉长-缩短周期（SSC）运动。平均在3分钟内出现疲劳。在雪橇运动前、运动后即刻以及运动后2小时、2天和4天进行了从50厘米高度的纵跳（DJ）测试。疲劳运动显示血乳酸浓度相对较高[12.5（标准差2.6）毫摩尔×升⁻¹]，血清肌酸激酶（CK）活性增加延迟2天[540（标准差407）单位×升⁻¹]。跳跃性能的初始下降（运动前 - 运动后即刻）与运动后早期恢复（运动后即刻至2小时）呈负相关（P < 0.05）。拉长结束时膝关节力矩的早期恢复与DJ性能延迟下降（2小时至2天）呈负相关（P < 0.01）。因此，DJ性能表现出初始下降，随后是早期恢复和二次下降。拉长结束时膝关节力矩的初始下降和早期恢复均与CK相应的初始增加（2小时后）（P < 0.05）和二次增加（2小时至2天）（P < 0.01）有关。提示膝关节功能的早期恢复以及初始下降可能取决于肌肉损伤程度。初始刚度的延迟下降（2小时至2天）与DJ着地时膝关节角度的相应变化呈负相关（P < 0.001）。这些相互作用表明，刚度调节的下降和着地前运动控制的调节可能归因于SSC运动后2天内的继发性肌肉损伤。因此，可以认为，在疲劳的SSC运动后，DJ性能的变化伴随着血清CK浓度相应增加以及DJ中刚度调节和运动控制相应恶化所观察到的肌肉损伤进展。
