Effect of two maximal isometric contractions on eccentric exercise-induced muscle damage of the elbow flexors
Effect of two maximal isometric contractions on eccentric exercise-induced muscle damage of the elbow flexors
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DOI：
10.1007/s00421-012-2581-8
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发表时间：
2013-06-01
影响因子：
3
通讯作者：
Nosaka, Kazunori
中科院分区：
文献类型：
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作者：
Chen, Trevor C.;Chen, Hsin-Lian;Nosaka, Kazunori
本研究探讨了在屈肘20A度时两次最大自主等长收缩(2MVC)对30个最大等速(60A°S(-1))偏心收缩所致的肌肉损伤的时间保护作用。65名未经训练的年轻男性被随机分配到不进行2MVC的对照组，或在MaxECC前即刻(0d)、2d(2d)、4d(4d)或7d(7d)进行2MVC的4个实验组之一(每组13例)。采用双向重复单因素方差分析方法，比较两组患者的最大等速(60A度)S(-1)向心力矩(MVC-CON)、最佳角度(OA)、活动范围、上臂周径、肌肉酸痛程度、血浆肌酸激酶活性和肌红蛋白浓度以及超声回声强度的变化。2MVC后，所有变量均无明显变化。MaxECC后，2d组和4d组所有变量的变化比对照组、0d组和7d组小16-62%(P<；0.05)。与4d组相比，2d组中除OA外的所有变量的变化都要小14-34%(P<；0.05)。对照组、0d组、7d组各指标变化相似。这些结果表明，在MaxECC前2-4天进行2MVC可以减轻肌肉损伤的程度，但如果在MaxECC之前立即或7天进行2MVC，则没有明显的效果。结果表明，2MVC的保护作用是相对短暂的，存在一个发挥保护作用的窗口。
This study investigated the time wise protective effect conferred by two maximal voluntary isometric contractions (2MVCs) at 20A degrees elbow flexion on muscle damage induced by 30 maximal isokinetic (60A degrees s(-1)) eccentric contractions of the elbow flexors (MaxECC). Sixty-five young untrained men were randomly assigned to a control group that did not perform 2MVCs, or one of four experimental groups (n = 13 per group) who performed 2MVCs either immediately (0d), 2 (2d), 4 (4d) or 7 days (7d) before MaxECC. Changes in maximal isokinetic (60A degrees s(-1)) concentric torque (MVC-CON), optimum angle (OA), range of motion, upper arm circumference, muscle soreness, plasma creatine kinase activity and myoglobin concentration, and ultrasound echo-intensity following MaxECC were compared among the groups by a two-way repeated measures ANOVA. No significant changes in any variables were evident following 2MVCs. The 2d and 4d groups showed 16-62 % smaller (P < 0.05) changes in all variables following MaxECC than the control, 0d and 7d groups. The 2d group showed 14-34 % smaller (P < 0.05) changes in all variables except for OA compared with the 4d group. The changes in the variables were similar among the control, 0d and 7d groups. These results show that 2MVCs that were performed between 2 and 4 days before MaxECC attenuated the magnitude of muscle damage, but no such effect was evident if the 2MVCs were performed immediately or 7 days before MaxECC. It is concluded that the protective effect conferred by 2MVCs is relatively short-lived, and there is a window for the effect to be conferred.