Røe C, Steingrímsdóttir O A, Knardahl S, Bakke E S, Vøllestad N K
Department of Physiology, National Institute of Occupational Health, PO Box 8149 Dep, 0033 Oslo, Norway.
J Electromyogr Kinesiol. 2006 Feb;16(1):103-13. doi: 10.1016/j.jelekin.2005.03.004. Epub 2005 Jun 6.
We determined the repeatability and correlations between force, endurance and muscle activity during isometric contractions over three years. Twenty-six subjects, with and without complaints of the shoulder and neck, performed standardized maximal and submaximal shoulder-abduction contractions and wrist extension-contractions at yearly intervals from 1997 to 1999. Peak forces developed during maximal contraction and the endurance times of submaximal contractions during shoulder abduction and wrist extension were measured. Electromyography (EMG) of muscle activity was recorded bilaterally from the upper trapezius, middle deltoid, and forearm extensor muscles. Root mean square EMG amplitudes were calculated. We found statistically significant associations between peak forces developed during wrist extension and shoulder abduction, and between endurance times of submaximal wrist extension and shoulder abduction. No statistically significant changes in peak force and EMG(peak) were found over the measurement years. The responses were not statistically significantly influenced by gender, or neck and shoulder pain. However, we observed considerable intra-individual variation in the inter-year measurements particularly for the responses to submaximal contraction. Such large variations represent a challenge when attempting to use the responses to interpret the effects of therapies.
我们在三年时间里确定了等长收缩过程中力量、耐力和肌肉活动之间的重复性及相关性。26名受试者，有或无肩颈不适，在1997年至1999年期间每年进行标准化的最大和次最大肩部外展收缩以及腕部伸展收缩。测量了最大收缩过程中产生的峰值力量以及肩部外展和腕部伸展过程中次最大收缩的耐力时间。双侧记录了上斜方肌、三角肌中部和前臂伸肌肌肉活动的肌电图（EMG）。计算了肌电图均方根振幅。我们发现腕部伸展和肩部外展过程中产生的峰值力量之间，以及次最大腕部伸展和肩部外展的耐力时间之间存在统计学显著关联。在测量年份中，峰值力量和肌电图（峰值）未发现统计学显著变化。这些反应在统计学上不受性别、颈部和肩部疼痛的显著影响。然而，我们观察到个体内年度间测量存在相当大的差异，特别是对于次最大收缩的反应。当试图用这些反应来解释治疗效果时，如此大的差异构成了挑战。
