Department of Exercise and Sport Science, University of Utah, 250 S 1850 E Room 241, Salt Lake City, UT 84112-0920, USA.
Med Sci Sports Exerc. 2010 Sep;42(9):1723-30. doi: 10.1249/MSS.0b013e3181d60ead.
Previous investigators have reported changes in maximal power after eccentric exercise. The influence of eccentric joint-specific power absorption on subsequent concentric joint-specific power production during multijoint actions has not been reported.
Our purposes were to determine the extent to which ankle, knee, and hip joint actions absorbed power during eccentric cycling (ECCcyc) and to evaluate changes in power produced by those joint actions during subsequent maximal concentric cycling (CONcyc). We hypothesized that joint actions that absorbed the most power during ECCcyc would exhibit the greatest reductions in power during subsequent maximal CONcyc.
Nineteen cyclists performed baseline trials of maximal single-leg CONcyc immediately before and 24 h after acute single-leg ECCcyc (5 min, 40% maximum single-leg CONcyc power). Pedal forces and limb kinematics were determined with a force-sensing pedal and instrumented spatial linkage system, respectively. Joint-specific powers were calculated using inverse dynamics and averaged over complete crank revolutions and over extension and flexion phases.
The largest power-absorbing actions during ECCcyc were eccentric knee extensor activity (-185 +/- 12 W) followed by eccentric hip extensor activity (-92 +/- 12 W). Power absorbed through ankle joint actions was small (-10 +/- 2 W). At 24 h, pedal power produced during maximal CONcyc was reduced by 11% +/- 3% relative to baseline. Compared with baseline, knee extension power was reduced by 19% +/- 0 7%, whereas hip extension power did not differ.
Power absorbed through eccentric knee extension actions significantly reduced knee extension power produced during subsequent maximal CONcyc. Even with reduced knee extensor function, participants were able to deliver 89% of their baseline power to the environment. These results have implications for individuals who must continue to perform multijoint activities after eccentric exercise.
本研究旨在确定在进行离心骑车（ECCcyc）时关节吸收了多少功率，并评估这些关节在随后的最大向心骑车（CONcyc）中产生的功率变化。我们假设在 ECCcyc 中吸收功率最多的关节动作，在随后的最大 CONcyc 中，其功率输出会减少最多。
19 名自行车运动员在急性单腿 ECCcyc（5 分钟，40%最大单腿 CONcyc 功率）前和 24 小时后进行最大单腿 CONcyc 的基线试验。使用测力脚踏板和仪器化空间连杆系统分别确定踏板力和肢体运动学。使用逆动力学计算关节特异性功率，并在整个曲柄旋转和伸展阶段进行平均。
ECCcyc 期间最大的功率吸收动作是离心膝伸肌活动（-185 +/- 12 W），其次是离心髋伸肌活动（-92 +/- 12 W）。踝关节的吸收功率很小（-10 +/- 2 W）。24 小时后，最大 CONcyc 时的踏板功率比基线降低了 11% +/- 3%。与基线相比，膝关节伸展功率降低了 19% +/- 0.7%，而髋关节伸展功率没有差异。
通过离心膝伸肌活动吸收的功率显著降低了随后最大 CONcyc 时的膝伸肌功率。即使膝关节伸肌功能下降，参与者仍能将 89%的基线功率传递到环境中。这些结果对于必须在离心运动后继续进行多关节活动的个体具有重要意义。
