Ghasemi Mehri, Olyaei Gholamreza, Bagheri Hossein, Talebian Saeed, Shadmehr Azadeh, Jalaei Shohreh
Department of Physical Therapy, Faculty of Rehabilitation, Tehran University of Medical Sciences, Iran.
J Back Musculoskelet Rehabil. 2012;25(2):95-101. doi: 10.3233/BMR-2012-0316.
The common description of muscular fatigue is the failure of muscle in maintaining a target force. Even in sustained contraction, when muscle force is held at a stable level, physiological, biomechanical and electromyographic changes can occur. The purpose of this study is to compare the effects of triceps surae (TS) fatigue on the torque, falling slope and electromyographic (EMG) parameters between athletes and non-athletes.
Nineteen healthy women (10 non-athletes and 9 basketball players) participated in this study. After warm-up, subjects performed one maximum voluntary contraction (MVC) followed by fatigue test including sustained maximum isometric contraction of TS until the peak torque (PT) decreased to 50% of maximum value. Immediately after the test, subjects were asked to perform one MVC; then, root mean square (RMS), median frequency (MDF), median frequency slope (MDF slope), PT, falling slope (FSL) and the amount of pain were measured.
In both groups shift of MDF slope to negative values, significant decrease of MDF and RMS occurred at the end of the fatigue test (P < 0.05). Immediately after the test, PT decreased significantly in both groups (P < 0.05), however, decrease of FSL was significant in non-athletes (P < 0.05) but not in athletes. After fatigue test, increase in Pain was significant in both groups (P < 0.05). Before fatigue test, at the end, and immediately after the test, MDF of non-athletes was more than athletes. There was no significant difference in RMS between the two groups.
Our findings suggest that TS fatigue affects EMG parameters, PT and pain in athletes and non-athletes similarly.
肌肉疲劳的常见描述是肌肉无法维持目标力量。即使在持续收缩过程中，当肌肉力量保持在稳定水平时，生理、生物力学和肌电图变化仍可能发生。本研究的目的是比较运动员和非运动员中腓肠肌（TS）疲劳对扭矩、下降斜率和肌电图（EMG）参数的影响。
19名健康女性（10名非运动员和9名篮球运动员）参与了本研究。热身之后，受试者进行一次最大自主收缩（MVC），随后进行疲劳测试，包括TS的持续最大等长收缩，直至峰值扭矩（PT）降至最大值的50%。测试结束后，立即要求受试者进行一次MVC；然后，测量均方根（RMS）、中位频率（MDF）、中位频率斜率（MDF斜率）、PT、下降斜率（FSL）和疼痛程度。
在两组中，疲劳测试结束时MDF斜率均向负值偏移，MDF和RMS显著降低（P < 0.05）。测试结束后，两组的PT均显著降低（P < 0.05），然而，非运动员的FSL降低显著（P < 0.05），而运动员则不然。疲劳测试后，两组的疼痛程度均显著增加（P < 0.05）。在疲劳测试前、结束时和结束后，非运动员的MDF均高于运动员。两组之间的RMS无显著差异。
我们的研究结果表明，TS疲劳对运动员和非运动员的EMG参数、PT和疼痛的影响相似。
