Low-intensity eccentric contractions attenuate muscle damage induced by subsequent maximal eccentric exercise of the kne
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ORIGINAL ARTICLE
Low-intensity eccentric contractions attenuate muscle damage induced by subsequent maximal eccentric exercise of the knee extensors in the elderly Trevor C. Chen • Wei-Chin Tseng • Guan-Ling Huang • Hsin-Lian Chen Kou-Wei Tseng • Kazunori Nosaka
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Received: 9 August 2012 / Accepted: 27 September 2012 / Published online: 12 October 2012 Ó Springer-Verlag Berlin Heidelberg 2012
Abstract 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 Communicated by Toshio Moritani. T. C. Chen (&) W.-C. Tseng G.-L. Huang H.-L. Chen Department of Physical Education, National Chiayi University, 85 Wenlong Village, Minsyong Township 62103, Chiayi County, Taiwan e-mail: [email protected] W.-C. Tseng Graduate Institute of Coaching Science, National Taiwan Sport University, Taoyuan County, Taiwan K.-W. Tseng Department of Physical Education and Health, Taipei Physical Education College, Taipei, Taiwan K. Nosaka School of Exercise and Health Sciences, Edith Cowan University, Joondalup, WA, Australia
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. Keywords Protective effect Muscle strength Delayed onset muscle soreness Creatine kinase Preconditioning
Introduction We experience muscle soreness in next days after performing unaccustomed exercise consisting of lengthening contractions [termed as ‘‘eccentric contractions’’ in this article based on Faulkner (2003)]. This type of muscle soreness is referre
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