Effect of human exposure to altitude on muscle endurance during isometric contractions

被引：0

作者：

F. Felici

A. Rosponi

P. Sbriccoli

M. Scarcia

I. Bazzucchi

M. Iannattone

机构：

[1] University Institute of Motor Sciences,

[2] Faculty of Motor Sciences,undefined

[3] Laboratory of Exercise Physiology,undefined

[4] Piazza Lauro De Bosis 15,undefined

[5] 00194 Rome,undefined

[6] Italy,undefined

[7] Post-graduate School of Specialization in Sport Medicine,undefined

[8] Faculty of Medicine,undefined

[9] University of Rome "La Sapienza",undefined

[10] P. le Aldo Moro 5,undefined

[11] 00185 Rome,undefined

[12] Italy,undefined

[13] S. Lucia Foundation,undefined

[14] Rehabilitation Hospital,undefined

[15] Via Ardeatina 306,undefined

[16] 00179,undefined

[17] Rome,undefined

[18] Italy,undefined

来源：

European Journal of Applied Physiology | 2001年 / 85卷

关键词：

Altitude Isometric endurance Electromyography Median frequency Non-linear analysis;

D O I：

暂无

中图分类号：

学科分类号：

摘要：

The aim of this study was to evaluate the influence of exposure to altitude on muscle endurance during isometric contractions. Six sedentary subjects were studied. Surface electromyograph (sEMG) activity was recorded from the right biceps brachii (BB) during exhausting isometric exercise at 80% maximal voluntary contraction. Experiments were performed before, during and 6 months after a 12 day stay at the EV-K2 laboratory (Nepal, 5,050 m above sea level). From the sEMG signals from BB, the median frequencies (fmed) were computed for consecutive 1 s epochs. The sEMG was also analysed using a non-linear tool, the recurrence quantification analysis, and the percentage of determinism (%DET) was then calculated. The haemoglobin saturation significantly decreased at altitude. The mean (SD) BB endurance time decreased from 22.4 (4) s to 18.3 (4.7) s (P<0.05). After exposure to altitude a significant variation in fmed and %DET slopes was observed. We concluded that during the first period of acclimatisation at altitude there was an impairment of isometric muscle endurance performance and there was also evidence of a modified myoelectric activity pattern suggesting a greater fatigability of the neuromuscular system.

引用

页码：507 / 512

页数：5