Thorstensson A, Grimby G, Karlsson J
J Appl Physiol. 1976 Jan;40(1):12-6. doi: 10.1152/jappl.1976.40.1.12.
Standardized measurements of dynamic strength of the kneee extensor muscles were performed in 25 healthy male subjects (17-37 yr) by means of isokinetic contractions, i.e., knee extensions with constant angular velocities. Overall variation between double determinations of maximal torque throughout the 90 degrees arc of motion (0 degrees = fully extended leg) averaged 10% for the different constant velocities chosen. At any given angle of the knee the torque produced was higher for isometric than for dynamic contractions. Dynamic torque decreased gradually with increased speed of shortening. Peak dynamic torque was reached at knee angles in the range: 55-66 degrees, with a displacement toward smaller knee angles with higher angular velocities. Correlations were demonstrated between peak torque produced at the highest speed of muscle shortening and percent as well as relative area of fast twitch fibers in the contracting muscle. In addition muscles with a high percentage of fast twitch fibers had the highest maximal contraction speeds. These observations on intact human skeletal muscle are consistent with earlier findings in animal skeletal muscle preparations.
通过等速收缩，即采用恒定角速度进行膝关节伸展，对25名健康男性受试者（17 - 37岁）的膝伸肌动态力量进行了标准化测量。在整个90度运动弧（0度 = 腿部完全伸展）内，对最大扭矩进行两次测定的总体变化，在所选择的不同恒定速度下平均为10%。在膝关节的任何给定角度，等长收缩产生的扭矩高于动态收缩。动态扭矩随着缩短速度的增加而逐渐降低。在膝关节角度55 - 66度范围内达到峰值动态扭矩，随着角速度增加，峰值向较小膝关节角度偏移。在肌肉缩短最高速度下产生的峰值扭矩与收缩肌肉中快肌纤维的百分比以及相对面积之间存在相关性。此外，快肌纤维百分比高的肌肉具有最高的最大收缩速度。这些对完整人体骨骼肌的观察结果与早期在动物骨骼肌制剂中的发现一致。
