排序方式: 共有4条查询结果,搜索用时 15 毫秒
1
1.
G. M. H?gg J. Robert M. Ojok 《European journal of applied physiology and occupational physiology》1997,75(3):263-267
As an alternative to a conventional endurance electromyogram (EMG) test for assessment of muscle capacity in the upper trapezius
muscle (isotonic test, IT), an isoelectric test (IE) has been investigated. Nine subjects performed the two endurance tests.
The tests were performed with a straight horizontal arm in the plane of the scapula. In IE, EMG amplitude was fed back to
the subject and the subject was instructed to maintain a constant EMG activity equal to the level with the arm unsupported.
Subjective ratings of local fatigue were obtained during the experiments. The EMG recordings from both tests were analysed
for the root mean square value as well as according to the mean power frequency (MPF) technique. All the subjects endured
maximal 15 min IE while in IT the median endurance was 11.9 min. Average subjective ratings of perceived fatigue increased
more in IT compared to IE. The average normalised MPF curve from IT increased while that from IE was unaffected. There was
a significant difference between the MPF results at 6 and 8 min. It is noteworthy that the MPF was higher in IT in spite of
a higher accumulated biomechanical load. It was concluded from these studies that the interpretation of decreased MPF as an
indicator of increased local muscle fatigue is doubtful at low contraction levels. It is suggested that an IE is a more appropriate
method for the functional evaluation of low threshold motor units of the upper trapezius muscle in research into occupational
disorders.
Accepted: 15 October 1996 相似文献
2.
3.
4.
1