O'Brien Thomas D, Reeves Neil D, Baltzopoulos Vasilios, Jones David A, Maganaris Constantinos N
Manchester Metropolitan University, Institute for Biomedical Research into Human Movement and Health, Manchester, UK.
Exp Physiol. 2009 Jun;94(6):731-8. doi: 10.1113/expphysiol.2008.045062. Epub 2009 Feb 27.
The present study investigated whether differences between adults and children in mechanical power during single-joint knee extension tasks and the complex multijoint task of jumping could be explained by differences in the quadriceps femoris muscle volume. Peak power was calculated during squat jumps, from the integral of the vertical force measured by a force plate, and during concentric knee extensions at 30, 90, 120, 180 and 240 deg s(-1), and muscle volume was measured from magnetic resonance images for 10 men, 10 women, 10 prepubertal boys and 10 prepubertal girls. Peak power during jumping and isokinetic knee extension was significantly higher in men than in women, and in both adult groups compared with children (P < 0.01), although there were no differences between boys and girls. When power was normalized to muscle volume, the intergroup differences ceased to exist for both tasks. Peak power correlated significantly with quadriceps volume (P < 0.01), with r(2) values of 0.8, 0.86, 0.81, 0.78 and 0.81 from isokinetic knee extension at angular velocities of 30, 90, 120, 180 and 240 deg s(-1), respectively, and with an r(2) value of 0.9 from squat jumps. These results indicate that the quadriceps femoris muscle volume accounts largely for the increase in power that occurs with maturation in the two genders not only in kinematically constrained knee extensions but also in multijoint tasks. Future studies should examine the role of other factors relating to the generation and transmission of contractile power, such as muscle architecture, tendon stiffness and external mechanical leverage.
本研究调查了在单关节伸膝任务和复杂的多关节跳跃任务中，成年人与儿童在机械功率上的差异是否可以通过股四头肌体积的差异来解释。在深蹲跳过程中，根据测力板测量的垂直力积分计算峰值功率；在膝关节以30、90、120、180和240度/秒（-1）进行向心伸展时计算峰值功率。通过磁共振成像测量了10名男性、10名女性、10名青春期前男孩和10名青春期前女孩的肌肉体积。男性在跳跃和等速伸膝过程中的峰值功率显著高于女性，且两个成年组均高于儿童（P<0.01），不过男孩和女孩之间没有差异。当功率按肌肉体积进行归一化时，两项任务的组间差异均不再存在。峰值功率与股四头肌体积显著相关（P<0.01），在30、90、120、180和240度/秒（-1）等速伸膝时的r（2）值分别为0.8、0.86、0.81、0.78和0.81，深蹲跳时的r（2）值为0.9。这些结果表明，股四头肌体积在很大程度上解释了随着成熟，两性在功率上的增加，这不仅体现在运动学受限的伸膝动作中，也体现在多关节任务中。未来的研究应考察与收缩功率产生和传递相关的其他因素的作用，如肌肉结构、肌腱刚度和外部机械杠杆作用。
