Ginn Karen A, Halaki Mark
Discipline of Biomedical Science, Sydney Medical School, The University of Sydney, Australia.
Discipline of Exercise and Sport Science, Faculty of Health Sciences, The University of Sydney, Australia.
J Electromyogr Kinesiol. 2015 Feb;25(1):8-13. doi: 10.1016/j.jelekin.2014.10.008. Epub 2014 Oct 27.
Because of its superficial location surface electrodes are commonly used to record latissimus dorsi (LD) activity. Despite the fact that the recommended electrode placement is over the belly where LD is quite thin no studies have investigated the possibility of signal contamination from muscles lying deep to LD. Therefore, the aim of this study was to determine the validity of using surface electrodes to record activity from LD. Eight asymptomatic subjects performed ramped isometric (0-100% maximum load) and dynamic (70% maximum load) shoulder tasks. Intramuscular electrodes were inserted into LD and the adjacent erector spinae. Surface electrodes were placed over LD around the intramuscular electrodes. Results indicated that while there was no difference in activity level or activation pattern (ICC>0.94) recorded by the two electrode types during shoulder tasks in which LD would be expected to be active (extension and adduction), significantly lower (p<0.05) LD activity was recorded via intramuscular electrodes during the shoulder flexion and abduction tasks. Therefore, recordings of LD activity by surface electrodes overestimate LD activity during shoulder tasks when this muscle would be expected to be activated at minimum levels. Erector spinae immediately deep to LD was confirmed as a source of crosstalk contamination.
由于背阔肌（LD）位置表浅，表面电极常用于记录其活动。尽管推荐的电极放置位置是在LD较薄的肌腹上方，但尚无研究探讨来自LD深层肌肉的信号污染可能性。因此，本研究的目的是确定使用表面电极记录LD活动的有效性。八名无症状受试者进行了斜坡等长收缩（0 - 100%最大负荷）和动态（70%最大负荷）肩部任务。将肌内电极插入LD及相邻的竖脊肌。表面电极放置在肌内电极周围的LD上方。结果表明，在预期LD会活跃的肩部任务（伸展和内收）中，两种电极类型记录的活动水平或激活模式无差异（组内相关系数>0.94），但在肩部屈曲和外展任务期间，通过肌内电极记录的LD活动显著更低（p<0.05）。因此，当预期该肌肉在肩部任务中以最低水平被激活时，表面电极记录的LD活动高估了LD活动。紧邻LD深层的竖脊肌被确认为串扰污染的来源。
