EpicWide, LLC, Baltimore, MD, USA.
Department of Health Sciences and Technology, Institute of Robotics and Intelligent Systems, ETH Zurich, Zurich, Switzerland.
Hum Factors. 2023 Nov;65(7):1491-1505. doi: 10.1177/00187208211050723. Epub 2021 Dec 8.
The effects of diverse periodic interventions on trapezius muscle fatigue and activity during a full day of computer work were investigated.
Musculoskeletal disorders, including trapezius myalgia, may be associated with repeated exposure to prolonged low-level activity, even during light upper-extremity tasks including computer work.
Thirty healthy adults participated in a study that simulated two 6-hour workdays of computer work. One workday involved imposed periodic passive and active interventions aimed at disrupting trapezius contraction monotony (Intervention day), whereas the other workday did not (Control day). Trapezius muscle activity was quantified by the 3-dimensional acceleration of the jolt movement of the acromion produced by electrically induced muscle twitches. The spatio-temporal distribution of trapezius activity was measured through high-density surface electromyography (HD-EMG).
The twitch acceleration magnitude in one direction was significantly different across measurement periods ( = 0.0156) on Control day, whereas no significant differences in any direction were observed ( > 0.05) on Intervention day. The HD-EMG from Intervention day showed that only significant voluntary muscle contractions (swing arms, Jacobson maneuver) induced a decrease in the muscle activation time and an increase in the spatial muscle activation areas ( < 0.01).
Disruption of trapezius monotonous activity via brief voluntary contractions effectively modified the ensuing contraction pattern (twitch acceleration along one axis, active epochs reduction, and larger spatial distribution). The observed changes support an associated reduction of muscle fatigue.
This study suggests that disruptive intervention activity is efficient in reducing the impact of trapezius muscle fatigue.
研究在一整天的计算机工作中，不同周期性干预对斜方肌疲劳和活动的影响。
包括斜方肌痛在内的肌肉骨骼疾病可能与反复暴露于长时间低水平活动有关，即使在包括计算机工作在内的上肢轻任务中也是如此。
30 名健康成年人参与了一项模拟两天 6 小时计算机工作的研究。一天的工作涉及强制性的周期性被动和主动干预，旨在打破斜方肌收缩的单调性（干预日），而另一天则不进行干预（对照日）。通过电诱发肌肉抽搐引起的肩峰的冲击运动的三维加速度来量化斜方肌活动。通过高密度表面肌电图（HD-EMG）测量斜方肌活动的时空分布。
在对照日，一个方向的抽搐加速度幅度在测量期间存在显著差异（=0.0156），而在干预日，任何方向均未观察到显著差异（>0.05）。干预日的 HD-EMG 显示，只有显著的自愿肌肉收缩（摆臂、Jacobson 手法）会导致肌肉激活时间减少和空间肌肉激活区域增加（<0.01）。
通过短暂的自愿收缩破坏斜方肌单调活动可以有效地改变随后的收缩模式（沿一个轴的抽搐加速度、主动期减少和更大的空间分布）。观察到的变化支持肌肉疲劳的减少。
本研究表明，中断干预活动可有效降低斜方肌疲劳的影响。
