神经肌肉疲劳对前交叉韧带重建术后个体及健康成年人股四头肌力量、激活情况和膝关节生物力学的影响
Effects of Neuromuscular Fatigue on Quadriceps Strength and Activation and Knee Biomechanics in Individuals Post-Anterior Cruciate Ligament Reconstruction and Healthy Adults.
作者信息
Thomas Abbey C, Lepley Lindsey K, Wojtys Edward M, McLean Scott G, Palmieri-Smith Riann M
出版信息
J Orthop Sports Phys Ther. 2015 Dec;45(12):1042-50. doi: 10.2519/jospt.2015.5785. Epub 2015 Oct 15.
STUDY DESIGN
Laboratory-based experiment using a pretest/posttest design.
OBJECTIVES
To determine the effects of neuromuscular fatigue on quadriceps strength and activation and sagittal and frontal plane knee biomechanics during dynamic landing following anterior cruciate ligament reconstruction (ACLR).
BACKGROUND
Impaired quadriceps central activation occurs post-ACLR, likely altering lower extremity biomechanics. Neuromuscular fatigue similarly reduces volitional muscle activation and impairs neuromuscular control. Upon return to full activity post-ACLR, individuals likely concurrently experience quadriceps central activation deficits and neuromuscular fatigue, though the effects of fatigue on muscle strength and activation and biomechanics post-ACLR are unknown.
METHODS
Seventeen individuals 7 to 10 months post-ACLR and 16 controls participated. Quadriceps strength and central activation ratio were recorded prefatigue and postfatigue, which was induced via sets of double-leg squats. Knee biomechanics were recorded during a dynamic landing activity prefatigue and postfatigue.
RESULTS
Both groups demonstrated smaller knee flexion (initial contact, P = .017; peak, P = .004) and abduction (initial contact, P = .005; peak, P = .009) angles postfatigue. The ACLR group had smaller peak knee flexion angles (P<.001) prefatigue and postfatigue than controls. Knee flexion moment was smaller in those post-ACLR than controls prefatigue (P<.001), but not postfatigue (P = .103). Controls had smaller knee flexion moments postfatigue (P = .001). Knee abduction moment was smaller in both groups postfatigue (P = .003). All participants demonstrated significantly lower strength (P<.001) and activation (P = .003) postfatigue.
CONCLUSION
Impaired strength, central activation, and biomechanics were present postfatigue in both groups, suggesting that neuromuscular fatigue may increase noncontact ACL injury risk. However, these changes were not exaggerated in those post-ACLR, likely because they already demonstrated a stiff-legged landing strategy prefatigue.
研究设计
采用实验前/实验后设计的基于实验室的实验。
目的
确定神经肌肉疲劳对前交叉韧带重建（ACLR）后动态着陆过程中股四头肌力量、激活情况以及矢状面和额状面膝关节生物力学的影响。
背景
ACLR后股四头肌中枢激活受损，可能会改变下肢生物力学。神经肌肉疲劳同样会降低随意性肌肉激活并损害神经肌肉控制。ACLR后恢复全面活动时，个体可能同时经历股四头肌中枢激活不足和神经肌肉疲劳，尽管疲劳对ACLR后肌肉力量、激活情况和生物力学的影响尚不清楚。
方法
17名ACLR后7至10个月的个体和16名对照组参与研究。在疲劳前和通过双腿深蹲组诱导疲劳后，记录股四头肌力量和中枢激活率。在疲劳前和疲劳后的动态着陆活动中记录膝关节生物力学情况。
结果
两组在疲劳后膝关节屈曲角度（初始接触，P = 0.017；峰值，P = 0.004）和外展角度（初始接触，P = 0.005；峰值，P = 0.009）均减小。ACLR组在疲劳前和疲劳后的膝关节屈曲峰值角度均小于对照组（P<0.001）。ACLR组在疲劳前膝关节屈曲力矩小于对照组（P<0.001），但在疲劳后无差异（P = 0.103）。对照组在疲劳后膝关节屈曲力矩较小（P = 0.001）。两组在疲劳后膝关节外展力矩均较小（P = 0.003）。所有参与者在疲劳后力量（P<0.001）和激活情况（P = 0.003）均显著降低。
结论
两组在疲劳后均出现力量、中枢激活和生物力学受损，提示神经肌肉疲劳可能增加非接触性ACL损伤风险。然而，这些变化在ACLR后个体中并未加剧，可能是因为他们在疲劳前已表现出僵硬的腿部着陆策略。
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