Department of Physical Therapy, College of Health Sciences, Sunmoon University, Asan-si, Chungcheongnam-do, Republic of Korea.
Digital Healthcare Institute, Sunmoon University, Asan-si, Chungcheongnam-do, Republic of Korea.
J Int Med Res. 2024 Jul;52(7):3000605241262186. doi: 10.1177/03000605241262186.
Existing isokinetic contractions are characterized using standardized angular velocities, which can induce differing adaptations. Here, we characterized the variation in the isokinetic parameters of knee extensors according to individualized angular velocity (IAV).
We performed a cross-sectional study of 19 young, healthy men. We measured the maximum angular velocity (MAV) of concentric knee extension using the isotonic mode of an isokinetic dynamometer. Isometric and isokinetic (at angular velocities corresponding to 100%, 70%, 40%, and 10% of each individual's MAV) knee extensor contractions were performed, and the peak torque and mean power were recorded.
Peak torque significantly decreased with increasing IAV (129.42 ± 25.04, 84.37 ± 20.97, and 56.42 ± 16.18 Nm at 40%, 70%, and 100%, respectively), except for isometric contraction (233.36 ± 47.85) and at 10% of MAV (208 ± 48.55). At the mean power, 10% of MAV (74.52 ± 20.84 W) was significantly lower than the faster IAV (176.32 ± 49.64, 161.53 ± 56.55, and 145.95 ± 50.64 W at 40%, 70%, and 100%, respectively), and 100% was significantly lower than 40%.
The optimized IAV for isokinetic contraction to improve power output while maintaining torque is 10% to 40% of MAV. IAV may reflect both the velocity and force components of power because individuals do not have the same angular velocity.
现有的等速收缩是使用标准化角速度来描述的，这会导致不同的适应。在这里，我们根据个体角速度（IAV）来描述膝关节伸肌等速参数的变化。
我们对 19 名年轻健康的男性进行了横断面研究。我们使用等速测力计的等张模式测量了膝关节伸肌的最大角速度（MAV）。进行了等长和等速（在对应于每个个体 MAV 的 100%、70%、40%和 10%的角速度下）膝关节伸肌收缩，并记录了峰值扭矩和平均功率。
峰值扭矩随 IAV 的增加而显著降低（40%、70%和 100%时分别为 129.42±25.04、84.37±20.97 和 56.42±16.18 Nm），但等长收缩和 10%MAV 时除外（233.36±47.85）。在平均功率方面，10%MAV（74.52±20.84 W）明显低于更快的 IAV（40%、70%和 100%时分别为 176.32±49.64、161.53±56.55 和 145.95±50.64 W），而 100%明显低于 40%。
在保持扭矩的同时提高功率输出的最佳等速收缩 IAV 为 10%至 40%的 MAV。IAV 可能反映了功率的速度和力量两个组成部分，因为个体的角速度并不相同。
