Klein Cassidy J D, Landry Scott C, Lattimer Lauren J
School of Kinesiology, Acadia University, Wolfville, Nova Scotia, Canada.
Orthop J Sports Med. 2023 Dec 22;11(12):23259671231215848. doi: 10.1177/23259671231215848. eCollection 2023 Dec.
Neuromuscular fatigue can increase the activation of antagonist muscles, thereby reducing the moment produced by the agonist. During the deceleration phase of landing, hip extensor and knee flexor muscles contract eccentrically to counteract the external hip flexion moment. Decreased hip flexion is associated with greater knee extensor moments and risk of injury.
To investigate sex-based differences in kinematics and muscle activity after neuromuscular fatigue of the hip extensors and knee flexors during dynamic single-leg tasks.
Controlled laboratory study.
In this study, 9 female (age, 22.3 ± 3.4 years) and 7 male participants (age, 21.3 ± 2.6 years) completed the triple hop (THop) for distance and single-leg drop-jump (SJump) tasks before and after a fatigue protocol consisting of eccentric hip extension and knee flexion. Motion capture and electromyography were used to compare lower extremity kinematics and muscular activation between the sexes.
During the THop, neuromuscular fatigue resulted in significantly decreased maximum hip flexion angles ( = .01), maximum knee flexion angles ( = .039), and an effect of sex on all hip flexion angles, where both sexes saw decreased hip flexion postfatigue ( = .033). A significant interaction of fatigue and sex on hip flexion angular velocity was observed during the SJump, indicating that men experienced an increase while women experienced a decrease in hip flexion angular velocities due to fatigue ( = .03). Gluteus maximus activation was increased, and erector spinae activation was decreased postfatigue in women during the THop ( = .053 and = .023, respectively).
Results indicate that men and women compensated differently after fatigue of the hip extensors and knee flexors.
Women more commonly assumed an erect landing posture associated with increased injury risk after fatigue of the hip extensors and knee flexors.
神经肌肉疲劳会增加拮抗肌的激活，从而降低主动肌产生的力矩。在着地的减速阶段，髋伸肌和膝屈肌进行离心收缩以抵消髋部的外部屈曲力矩。髋部屈曲减少与更大的膝伸肌力矩及受伤风险相关。
研究在动态单腿任务中，髋伸肌和膝屈肌出现神经肌肉疲劳后，男女在运动学和肌肉活动方面基于性别的差异。
对照实验室研究。
在本研究中，9名女性（年龄22.3±3.4岁）和7名男性参与者（年龄21.3±2.6岁）在由髋部伸展和膝部屈曲组成的疲劳方案前后，完成了远距离三级跳（THop）和单腿下落跳（SJump）任务。使用动作捕捉和肌电图来比较两性之间的下肢运动学和肌肉激活情况。
在三级跳过程中，神经肌肉疲劳导致最大髋部屈曲角度显著减小（P = 0.01），最大膝部屈曲角度显著减小（P = 0.039），并且性别对所有髋部屈曲角度均有影响，两性在疲劳后髋部屈曲均减小（P = 0.033）。在单腿下落跳过程中，观察到疲劳和性别对髋部屈曲角速度有显著交互作用，表明由于疲劳，男性的髋部屈曲角速度增加而女性的减小（P = 0.03）。在三级跳过程中，女性疲劳后臀大肌激活增加，竖脊肌激活减少（分别为P = 0.053和P = 0.023）。
结果表明，髋伸肌和膝屈肌疲劳后，男性和女性的代偿方式不同。
女性在髋伸肌和膝屈肌疲劳后更常采取与受伤风险增加相关的直立着地姿势。
