Østensvik Tove, Veiersted Kaj Bo, Nilsen Petter
Department of Forest Resources, Norwegian Forest and Landscape Institute, Høgskoleveien 8, 1432 As, Norway.
J Electromyogr Kinesiol. 2009 Apr;19(2):283-94. doi: 10.1016/j.jelekin.2007.07.005. Epub 2007 Sep 27.
The purpose of this paper was to describe and evaluate different aspects of muscle activity patterns associated with musculoskeletal discomfort/pain.
Surface electromyography (sEMG) of the right upper trapezius and the right extensor digitorum muscles was conducted continuously during one working day in 19 male forest machine operators driving harvesters, 20 driving forwarders and 20 researchers at the Forest Research Institute. Perceived discomfort/pain in the right side of the neck and the right forearm was rated morning, noon and afternoon with Borg's CR-10 scale. Static, median and peak levels of muscle activity were analyzed and the number and total duration of EMG gaps (muscular rest) were calculated. Sustained low-level muscle activity (SULMA) was defined as continuous muscle activity above 0.5% of the maximal EMG activity quantified into 10 periods of predetermined duration intervals from 1.6 to 5s up to above 20 min. The number of SULMA periods is presented within each interval and as cumulative periods above the already determined levels. The operators handled control levers seated in a fixed position while the researchers performed mainly PC work and other varied tasks.
A positive correlation was found between discomfort/pain in the right upper trapezius muscle region in the afternoon and cumulative SULMA periods above 10 min duration, and a negative correlation to cumulative SULMA periods also including the short durations. No specified patterns were found for discomfort/pain in the right extensor digitorum or for the other EMG measurements. All EMG measurements distinguished to some extent between the occupational groups, especially between machine operators driving harvesters and researchers.
Number of SULMA periods longer than 10 min per hour was positively correlated, and predominantly short periods were negatively correlated, to complaints in the neck region. This seems promising in order to find duration limits for sustained low-level muscle activity as a risk factor for musculoskeletal disorders.
本文旨在描述和评估与肌肉骨骼不适/疼痛相关的肌肉活动模式的不同方面。
对19名驾驶收割机的男性森林机械操作员、20名驾驶转运车的操作员以及森林研究所的20名研究人员，在一个工作日期间持续进行右侧斜方肌和右侧指伸肌的表面肌电图（sEMG）检测。使用博格CR-10量表在上午、中午和下午对颈部右侧和右前臂的感知不适/疼痛进行评分。分析肌肉活动的静态、中位和峰值水平，并计算肌电图间隙（肌肉休息）的数量和总持续时间。持续低水平肌肉活动（SULMA）定义为在1.6至5秒直至超过20分钟的10个预定持续时间间隔内，高于最大肌电图活动0.5%的连续肌肉活动。给出每个间隔内SULMA时段的数量以及高于已确定水平的累积时段数量。操作员坐在固定位置操作控制杆，而研究人员主要进行电脑工作和其他各种任务。
发现下午右上斜方肌区域的不适/疼痛与持续时间超过10分钟的累积SULMA时段呈正相关，与包括短持续时间的累积SULMA时段呈负相关。在右侧指伸肌的不适/疼痛或其他肌电图测量中未发现特定模式。所有肌电图测量在一定程度上区分了职业组，特别是驾驶收割机的机器操作员和研究人员之间。
每小时持续时间超过10分钟的SULMA时段数量与颈部区域的不适呈正相关，而主要是短时段与颈部区域的不适呈负相关。这对于找到持续低水平肌肉活动作为肌肉骨骼疾病风险因素的持续时间限制似乎很有前景。
