National Institute of Occupational Health, PO Box 8149 Dep, 0033 Oslo, Norway.
Scand J Work Environ Health. 2013 Jul;39(4):390-400. doi: 10.5271/sjweh.3357. Epub 2013 Mar 14.
This study aimed to evaluate if sustained trapezius muscle activity predicts neck and shoulder pain over a 2.5-year period.
Forty young adults (15 hairdressers, 14 electricians, 5 students and 6 with various work) were followed during their first years of working life. Self-reported neck and shoulder pain during the last four weeks was assessed seven times over the observational period. Upper-trapezius muscle activity was measured during a full working day by bilateral surface electromyography (EMG) at baseline (winter 2006/7). Sustained trapezius muscle activity was defined as continuous muscle activity with amplitude >0.5% EMGmax lasting >4 minutes. The relative time of sustained muscle activity during the working day was calculated and further classified into low (0-29%), moderate (30-49%) and high (50-100%) level groups.
Generalized estimating equations (GEE), adjusted for time, gender, mechanical workload, control-over-work intensity, physical activity, tobacco use, and prior neck and shoulder pain, showed that participants with a high level of sustained muscle activity had a rate of neck and shoulder pain three times higher than the low level group during a 2.5-year period. The association was strongest at the same time and shortly after the EMG measurement, indicating a time-lag of ≤6 months.
The results support the hypothesis that sustained trapezius muscle activity is associated with neck and shoulder pain. This association was strongest analyzing cross-sectional and short-term effects.
本研究旨在评估斜方肌持续活动是否可预测 2.5 年内的颈肩部疼痛。
40 名年轻成年人（15 名理发师、14 名电工、5 名学生和 6 名从事不同工作者）在其工作生涯的最初几年接受了随访。在观察期内，通过 7 次评估，共评估了参与者在过去 4 周内的颈肩部疼痛情况。在基线（2006/07 年冬季），通过双侧表面肌电图（EMG）对斜方肌全天的活动进行测量。将持续的斜方肌活动定义为振幅>0.5%EMGmax、持续时间>4 分钟的连续肌肉活动。计算了全天工作中持续肌肉活动的相对时间，并进一步分为低（0-29%）、中（30-49%）和高（50-100%）水平组。
调整时间、性别、机械工作量、对工作强度的控制、体力活动、吸烟状况和既往颈肩部疼痛情况后，使用广义估计方程（GEE）进行分析，结果显示，在 2.5 年内，高持续肌肉活动水平的参与者颈肩部疼痛的发生率是低水平组的 3 倍。在同一时间和 EMG 测量后不久，这种关联最强，表明存在≤6 个月的时间滞后。
研究结果支持这样一种假设，即斜方肌持续活动与颈肩部疼痛有关。这种关联在分析横断面和短期效应时最强。
