Hofmijster Mathijs J, VAN Soest A J, DE Koning Jos J
Faculty of Human Movement Sciences, Research Institute MOVE, Vrije Universiteit Amsterdam, The Netherlands.
Med Sci Sports Exerc. 2008 Jun;40(6):1101-10. doi: 10.1249/MSS.0b013e3181668671.
In rowing, the athlete has to maximize power output and to minimize energy losses to processes unrelated to average shell velocity. The contribution of velocity efficiency (evelocity; the fraction of mechanical power not lost to velocity fluctuations) to rowing performance in relation to the contributions of maximum oxygen uptake (V[spacing dot above]O2max) and gross efficiency (egross) was investigated. Relationships between evelocity and movement execution were determined.
Twenty-two well-trained female rowers participated in two testing sessions. In the first session, they performed a 2000-m time trial on a modified rowing ergometer that allowed for power losses due to velocity fluctuations. The V[spacing dot above]O2max, the evelocity, and the amount of rower-induced impulse fluctuations (RIIF) due to horizontal handle and foot stretcher forces were determined in a steady state part of the time trial. RIIF was used as a measure of movement execution. In the second session, egross was determined at submaximal intensity.
As expected, V[spacing dot above]O2max accounted for the major part of explained variance in the 2000-m time (53%, P < 0.001). Velocity efficiency accounted for a further 14%, egross for 11% (P < 0.05). Negative correlations were found between evelocity and RIIF values of several discreet intervals within a stroke cycle. The results suggest that optimal timing of forces applied to the ergometer will help minimizing power loss to velocity fluctuations.
This study indicates that a relationship exists between performance and evelocity. Furthermore, evelocity appears to be related to movement execution, in particular the timing of handle and foot stretcher forces.
在赛艇运动中,运动员必须使功率输出最大化,并将与平均艇速无关的过程中的能量损失降至最低。研究了速度效率(ev ;未因速度波动而损失的机械功率分数)对赛艇成绩的贡献与最大摄氧量(V̇O₂max)和总效率(egross)的贡献之间的关系。确定了速度效率与动作执行之间的关系。
22名训练有素的女子赛艇运动员参加了两次测试。在第一次测试中,她们在一台经过改装的赛艇测功仪上进行了2000米计时赛,该测功仪允许因速度波动而产生功率损失。在计时赛的稳定状态部分,测定了V̇O₂max、ev 和由于水平手柄和脚蹬力引起的划桨者诱发的冲量波动(RIIF)量。RIIF被用作动作执行的指标。在第二次测试中,在次最大强度下测定了egross。
正如预期的那样,V̇O₂max在2000米比赛时间的解释方差中占主要部分(53%,P < 0.001)。速度效率进一步占14%,总效率占11%(P < 0.05)。在一个划桨周期内的几个离散区间的ev 和RIIF值之间发现了负相关。结果表明,施加在测功仪上的力的最佳时机将有助于将速度波动造成的功率损失降至最低。
本研究表明成绩与ev 之间存在关系。此外,速度效率似乎与动作执行有关,特别是手柄和脚蹬力的时机。