Department of Physical Education, National Chiayi University, 85 Wenlong Village, Minsyong Township 62103, Chiayi County, Taiwan.
Eur J Appl Physiol. 2013 Apr;113(4):1005-15. doi: 10.1007/s00421-012-2517-3. Epub 2012 Oct 12.
This study investigated whether low-intensity eccentric contractions of the knee extensors would attenuate the magnitude of muscle damage induced by maximal eccentric exercise of the same muscle performed 7 days later using elderly individuals. Healthy older men (66.4 ± 4.6 years) were assigned to control or experimental (Exp) group (n = 13 per group). The control group performed six sets of ten maximal eccentric contractions (MaxECC) of the knee extensors of non-dominant leg. The Exp group performed six sets of ten low-intensity eccentric contractions of the knee extensors on a leg extension machine by lowering a weight of 10 % maximal voluntary isometric knee extension strength (10 %ECC) 7 days prior to MaxECC. Changes in maximal voluntary isokinetic concentric torque (MVC-CON), angle at peak torque, range of motion (ROM), upper thigh circumference, muscle soreness, plasma creatine kinase activity and myoglobin (Mb) concentration and B-mode ultrasound echo-intensity before and for 5 days after MaxECC were compared between groups by a mixed factor ANOVA. No significant changes in any variables were observed following 10 %ECC. Following MaxECC, all variables changed significantly, and changes in all variables except for angle at peak torque were significantly different between groups. MVC-CON and ROM decreased smaller and recovered faster (P < 0.05) for Exp than control group, and changes in other variables were smaller (P < 0.05) for Exp group compared with control group. These results suggest that preconditioning knee extensor muscles with low-intensity eccentric contractions was effective for attenuating muscle damage induced by subsequent MaxECC of the knee extensors for elderly individuals.
本研究旨在探讨低强度离心收缩是否会减轻 7 天后同一肌肉进行最大离心运动引起的肌肉损伤程度。选择健康的老年男性（66.4±4.6 岁），分为对照组和实验组（每组 13 人）。对照组进行 6 组 10 次非优势侧膝关节伸肌的最大离心收缩（MaxECC）。实验组在 7 天前进行 6 组 10 次膝关节伸肌的低强度离心收缩，在腿伸展机上降低 10%最大自主等长膝关节伸展力量（10%ECC）。通过混合因子方差分析比较 MaxECC 前后 5 天两组最大自主等速向心扭矩（MVC-CON）、峰值扭矩角度、运动范围（ROM）、大腿上部周长、肌肉酸痛、血浆肌酸激酶活性和肌红蛋白（Mb）浓度以及 B 型超声回波强度的变化。10%ECC 后，所有变量均无显著变化。在 MaxECC 后，所有变量均发生显著变化，除峰值扭矩角度外，所有变量的变化在两组间均有显著差异。与对照组相比，实验组的 MVC-CON 和 ROM 减小较小且恢复较快（P<0.05），其他变量的变化也较小（P<0.05）。这些结果表明，对膝关节伸肌进行低强度离心收缩预处理可有效减轻老年人随后进行的膝关节伸肌最大离心收缩引起的肌肉损伤。
