Wright Cynthia J, Arnold Brent L
Health and Physical Education Dept, Marywood University, Scranton, PA, USA.
J Sport Rehabil. 2012 May;21(2):127-36. doi: 10.1123/jsr.21.2.127. Epub 2011 Nov 16.
Force sense (FS), the proprioceptive ability to detect muscle-force generation, has been shown to be impaired in individuals with functional ankle instability (FAI). Fatigue can also impair FS in healthy individuals, but it is unknown how fatigue affects FS in individuals with FAI.
To assess the effect of fatigue on ankle-eversion force-sense error in individuals with and without FAI.
Case control with repeated measures.
Sports medicine research laboratory.
32 individuals with FAI and 32 individuals with no ankle sprains or instability in their lifetime. FAI subjects had a history of ≥1 lateral ankle sprain and giving-way ≥1 episode per month.
Three eversion FS trials were captured per load (10% and 30% of maximal voluntary isometric contraction) using a load cell before and after a concentric eversion fatigue protocol.
Trial error was the difference between the target and reproduction forces. Constant error (CE), absolute error (AE), and variable error (VE) were calculated from 3 trial errors. A Group × Fatigue × Load repeated-measures ANOVA was performed for each error.
There were no significant 3-way interactions or 2-way interactions involving group (all P > .05). CE and AE had a significant 2-way interaction between load and fatigue (CE: F1,62 = 8.704, P = .004; AE: F1,62 = 4.024, P = .049), and VE had a significant main effect for fatigue (F1,62 = 5.130, P = .027), all of which indicated increased FS error with fatigue at 10% load. However, at 30% load only VE increased with fatigue. The FAI group had greater error as measured by AE (F1,62 = 4.571, P = .036) but not CE or VE (P > .05).
Greater AE indicates that FAI individuals are less accurate in their force production. Fatigue impaired force sense in all subjects equally. These deficits provide evidence of impaired proprioception with fatigue and in individuals with FAI.
力觉（FS）是一种检测肌肉力量产生的本体感受能力，已被证明在功能性踝关节不稳（FAI）患者中受损。疲劳也会损害健康个体的力觉，但尚不清楚疲劳如何影响FAI患者的力觉。
评估疲劳对有无FAI个体的踝关节外翻力觉误差的影响。
重复测量的病例对照研究。
运动医学研究实验室。
32名FAI患者和32名一生中无踝关节扭伤或不稳的个体。FAI受试者有≥1次外侧踝关节扭伤史，且每月≥1次打软腿发作。
在同心外翻疲劳方案前后，使用测力传感器对每个负荷（最大自主等长收缩的10%和30%）进行三次外翻FS试验。
试验误差为目标力与再现力之间的差值。根据3次试验误差计算恒定误差（CE）、绝对误差（AE）和可变误差（VE）。对每个误差进行组×疲劳×负荷重复测量方差分析。
未发现涉及组别的显著三因素交互作用或二因素交互作用（所有P>.05）。CE和AE在负荷与疲劳之间存在显著的二因素交互作用（CE：F1,62 = 8.704，P =.004；AE：F1,62 = 4.024，P =.049），VE在疲劳方面有显著的主效应（F1,62 = 5.130，P =.027），所有这些均表明在10%负荷时，疲劳会增加FS误差。然而，在30%负荷时，只有VE随疲劳增加。以AE衡量，FAI组的误差更大（F1,62 = 4.571，P =.036），但CE或VE则不然（P>.05）。
更大的AE表明FAI个体在力量产生方面准确性较低。疲劳对所有受试者的力觉损害程度相同。这些缺陷为疲劳和FAI个体本体感觉受损提供了证据。
