MacIntosh B R, Herzog W, Suter E, Wiley J P, Sokolosky J
Human Performance Laboratory, Faculty of Physical Education, University of Calgary, Canada.
Eur J Appl Physiol Occup Physiol. 1993;67(6):499-506. doi: 10.1007/BF00241645.
It has been reported that there is a relationship between power output and fibre type distribution in mixed muscle. The strength of this relationship is greater in the range of 3-8 rad.s-1 during knee extension compared to slower or faster angular knee extensor speeds. A mathematical model of the force: velocity properties of muscle with various combinations of fast- and slow-twitch fibres may provide insight into why specific velocities may give better predictions of fibre type distribution. In this paper, a mathematical model of the force:velocity relationship for mixed muscle is presented. This model demonstrates that peak power and optimal velocity should be predictive of fibre distribution and that the greatest fibre type discrimination in human knee extensor muscles should occur with measurement of power output at an angular velocity just greater than 7 rad.s-1. Measurements of torque:angular velocity relationships for knee extension on an isokinetic dynamometer and fibre type distribution in biopsies of vastus lateralis muscles were made on 31 subjects. Peak power and optimal velocity were determined in three ways: (1) direct measurement, (2) linear regression, and (3) fitting to the Hill equation. Estimation of peak power and optimal velocity using the Hill equation gave the best correlation with fibre type distribution (r < 0.5 for peak power or optimal velocity and percentage of fast-twitch fibres). The results of this study confirm that prediction of fibre type distribution is facilitated by measurement of peak power at optimal velocity and that fitting of the data to the Hill equation is a suitable method for evaluation of these parameters.
据报道，混合肌肉的功率输出与纤维类型分布之间存在关联。与较慢或较快的膝关节伸展角速度相比，在膝关节伸展过程中，3-8弧度·秒-1范围内这种关系的强度更大。一个包含不同快肌纤维和慢肌纤维组合的肌肉力-速度特性数学模型，可能有助于深入了解为何特定速度能更好地预测纤维类型分布。本文提出了一个混合肌肉力-速度关系的数学模型。该模型表明，峰值功率和最佳速度应能预测纤维分布，并且在人类膝关节伸肌中，当测量角速度略大于7弧度·秒-1时的功率输出时，纤维类型的区分最为明显。对31名受试者进行了等速测力计上膝关节伸展的扭矩-角速度关系测量以及股外侧肌活检中的纤维类型分布测量。通过三种方式确定峰值功率和最佳速度：（1）直接测量，（2）线性回归，（3）拟合希尔方程。使用希尔方程估算峰值功率和最佳速度与纤维类型分布的相关性最佳（峰值功率或最佳速度与快肌纤维百分比的r<0.5）。本研究结果证实，通过测量最佳速度下的峰值功率有助于预测纤维类型分布，并且将数据拟合到希尔方程是评估这些参数的合适方法。
