Kim Youkyung, Youm Changhong, Son Minji, Kim Jinhee, Lee Myeounggon
Biomechanics Laboratory, College of Health Sciences, Dong-A University, Busan, Republic of Korea.
Biomechanics Laboratory, College of Health Sciences, Dong-A University, Busan, Republic of Korea; Department of Health Care and Science, College of Health Sciences, Dong-A University, Busan, Republic of Korea.
Knee. 2017 Dec;24(6):1342-1349. doi: 10.1016/j.knee.2017.09.007. Epub 2017 Sep 30.
Sporting situations include instances of continuous and/or integrated movements. However, the effect of fatigue on the performance of these movements remains unclear.
To investigate the effect of knee flexor and extensor fatigue on the shock absorption strategy of the lower limb during cutting movements performed after jump landings.
Twenty-four healthy participants performed cutting movements following jump landings from two heights - 30cm and 40cm - and under three levels of lower limb fatigue: pre-fatigue (100% peak knee extension torque), and post-fatigue 50% (post-50%) and 30% (post-30%) peak knee extension torque. Fatigue was induced by repeated isokinetic flexion/extension of the knee (60°/s).
Compared to the pre-fatigue condition, power and work at the knee joint decreased under both post-50% and post-30% conditions (P<0.001), while the work performed by the ankle (P<0.001) increased significantly. An increase in height from 30cm to 40cm was associated with an increase in the range of motion of the ankle (P<0.001) and knee (P=0.022), peak vertical ground reaction force (P<0.001), rate of loading (P<0.001), knee stiffness (P=0.026) and peak power of the knee (P<0.001), as well as the work performed by the knee (P<0.001) and hip (P<0.001) joints.
Under substantial muscle fatigue the proportion of shock absorption contributed by the knee for cutting movements performed after jump landings from a height of 40cm decreased; there was an adaptive increase in the contribution by the ankle.
运动场景包含连续和/或整合动作的情况。然而，疲劳对这些动作表现的影响仍不明确。
研究膝关节屈伸肌疲劳对跳跃落地后进行的切入动作中下肢减震策略的影响。
24名健康参与者从30厘米和40厘米两个高度跳跃落地后进行切入动作，并处于三种下肢疲劳水平：疲劳前（膝关节伸展峰值扭矩的100%）、50%疲劳后（50%后）和30%疲劳后（30%后）的膝关节伸展峰值扭矩。通过膝关节反复等速屈伸（60°/秒）诱导疲劳。
与疲劳前状态相比，在50%后和30%后两种情况下，膝关节的功率和功均下降（P<0.001），而踝关节所做的功（P<0.001）显著增加。从30厘米增加到40厘米的高度与踝关节（P<0.001）和膝关节（P=0.022）的运动范围增加、垂直地面反作用力峰值（P<0.001）、加载速率（P<0.001）、膝关节刚度（P=0.026）和膝关节峰值功率（P<0.001）以及膝关节（P<0.001）和髋关节（P<0.001）所做的功相关。
在肌肉严重疲劳的情况下，从40厘米高度跳跃落地后进行切入动作时，膝关节的减震比例下降；踝关节的贡献有适应性增加。
