Kellis Eleftherios, Liassou Christina
Department of Physical Education and Sports Sciences at Serres, Aristotle University of Thessaloniki, Thessaloniki, Greece.
J Orthop Sports Phys Ther. 2009 Mar;39(3):210-20. doi: 10.2519/jospt.2009.2859.
Controlled laboratory study.
To compare the changes in lower limb sagittal kinematics in running after a knee fatigue protocol with those observed after an ankle fatigue protocol.
Impaired force-generating ability of specific muscles may affect running mechanics, with negative implications for injury occurrence and performance. Identifying the strategies used to compensate for fatigue of selected muscles may assist in the design of more effective exercise programs for injury prevention and performance enhancement in running.
Sagittal plane kinematic data and the electromyographic (EMG) signal of the vastus medialis (VM), gastrocnemius (GAS), and biceps femoris (BF) muscles were collected from 15 females running at 3.61 m/s on a treadmill prior to, and following, an isokinetic knee extension/flexion and, on a separate day, an ankle plantar flexion/dorsiflexion fatigue protocol performed at 120 degrees/s.
Ankle muscle fatigue caused decreased ankle dorsiflexion, while knee fatigue caused increased knee flexion at initial contact (P<.05). Both protocols increased knee flexion angle at toe-off, as well as the amplitude of GAS and VM EMG signal, with the hip more extended after knee fatigue and the ankle more plantar flexed after ankle muscle fatigue. Ankle muscle fatigue caused a significant increase in hip extensionand ankle plantar flexion angular velocity, and a decline of BF EMG signal during the swing phase (P<.05). Knee muscle fatigue decreased hip and knee flexion angular velocity and increased BF EMG signal during the swing phase (P<.05).
Localized muscle fatigue effects on sagittal kinematics differed between the 2 protocols. However, the strategy used to compensate for fatigue was similar for both protocols: to protect the joints at initial impact and to prevent impairments in performance during toeoff and swing phase.
对照实验室研究。
比较在膝关节疲劳方案后与踝关节疲劳方案后跑步时下肢矢状面运动学的变化。
特定肌肉的力量产生能力受损可能会影响跑步力学，对损伤发生和运动表现产生负面影响。确定用于补偿所选肌肉疲劳的策略可能有助于设计更有效的运动计划，以预防跑步损伤并提高运动表现。
在等速膝关节伸展/屈曲之前和之后，以及在单独的一天，以120度/秒进行踝关节跖屈/背屈疲劳方案后，从15名以3.61米/秒的速度在跑步机上跑步的女性中收集矢状面运动学数据以及股内侧肌（VM）、腓肠肌（GAS）和股二头肌（BF）的肌电图（EMG）信号。
踝关节肌肉疲劳导致踝关节背屈减少，而膝关节疲劳导致初始接触时膝关节屈曲增加（P<0.05）。两种方案均增加了离地时的膝关节屈曲角度以及GAS和VM肌电图信号的幅度，膝关节疲劳后髋关节更伸展，踝关节肌肉疲劳后踝关节更跖屈。踝关节肌肉疲劳导致髋关节伸展和踝关节跖屈角速度显著增加，并且在摆动期BF肌电图信号下降（P<0.05）。膝关节肌肉疲劳降低了髋关节和膝关节屈曲角速度，并在摆动期增加了BF肌电图信号（P<0.05）。
两种方案对矢状面运动学的局部肌肉疲劳影响不同。然而，两种方案用于补偿疲劳的策略相似：在初始冲击时保护关节，并在离地和摆动期防止运动表现受损。
