Introduction

Cervical extensor muscle (CEM) fatigue causes decrements in upper limb proprioceptive accuracy during constrained single-joint tasks. This study used a novel humeral rotation joint position sense (JPS) measurement device to compare JPS accuracy in participants who received acute CEM fatigue vs. non-fatigued controls.

Methods

Participants had vision occluded and were passively guided into postures of internal humeral rotation from a baseline posture before and after a CEM fatigue or control protocol. Mixed model repeated measures ANOVAs were used to verify fatigue and compared absolute, constant, and variable JPS error between groups.

Results

CEM fatigue was verified via pre-post reduction in CEM strength, and myoelectric indicators of fatigue. However, between-group comparisons of absolute, constant, and variable JPS error were not statistically significant, despite having large effect sizes.

Discussion

Contrary to prevailing literature, unconstrained humeral rotation JPS did not appear to be affected by CEM fatigue in this study. However, between-group differences in JPS error were dwarfed by inter-trial variability, which likely arose due to the unconstrained nature of this task, conflating chances for a Type II error. Future research should perform a kinematic analysis of task constraints to highlight potential compensatory mechanisms obscuring significant findings in this otherwise robust effect.

中文翻译：

---

颈部肌肉疲劳对肩肱骨旋转关节位置感的影响

简介

在受限的单关节任务中，颈伸肌 (CEM) 疲劳会导致上肢本体感觉的准确性下降。本研究使用一种新型肱骨旋转关节位置感测 (JPS) 测量装置来比较接受急性 CEM 疲劳与非疲劳对照的参与者的 JPS 准确性。

方法

在 CEM 疲劳或控制方案之前和之后，参与者的视力被遮挡，并被被动引导到从基线姿势开始的肱骨内旋姿势。混合模型重复测量方差分析用于验证疲劳并比较组之间的绝对、恒定和可变 JPS 误差。

结果

CEM 疲劳通过 CEM 强度的前后降低和疲劳的肌电指标进行验证。然而，尽管具有很大的效应量，但绝对、恒定和可变 JPS 误差的组间比较在统计学上并不显着。

讨论

与流行的文献相反，在本研究中，不受约束的肱骨旋转 JPS 似乎不受 CEM 疲劳的影响。然而，JPS 错误的组间差异与试验间的差异相形见绌，这可能是由于这项任务的不受约束的性质，混淆了 II 类错误的机会。未来的研究应该对任务约束进行运动学分析，以突出潜在的补偿机制，这些机制掩盖了这种强大的影响中的重要发现。