title: Muscle damage protection by low-intensity eccentric contractions remains for 2 weeks but not 3 weeks.
abstract: This study investigated the hypothesis that the protective effect conferred by a low-intensity eccentric exercise against maximal eccentric exercise would not last more than a week. Untrained men (21.3 ± 1.6 years) were allocated into either a control or one of four repeated bout groups (n = 13 per group). The repeated bout groups performed 30 low-intensity eccentric contractions (ECC) of the elbow flexors with a dumbbell set at 10% of maximal isometric strength (10%-ECC) either 2 days, 7 days (1 week), 14 days (2 weeks) or 21 days (3 weeks) before 30 maximal eccentric contractions (Max-ECC). The control group performed Max-ECC only. Changes in maximal voluntary contraction strength, optimum angle, range of motion, upper arm circumference, muscle soreness, plasma creatine kinase activity and myoglobin concentration, and ultrasound echo-intensity following 10%-ECC were analysed by a one-way repeated measures ANOVA. Changes in the variables following Max-ECC were compared among the groups by a two-way repeated measures ANOVA. The 10%-ECC did not change any variables, showing no indication of muscle damage. The changes in all variables following Max-ECC were smaller (P < 0.05) for 2-day, 1- and 2-week groups than control group, without significant differences between 2-day and 1-week groups. The 2-week group showed greater (P < 0.05) changes in all variables compared with 2-day and 1-week groups. Changes in the variables were similar between 3-week and control groups, except for muscle soreness showing smaller (P < 0.05) changes for 3-week group. These results suggest that non-damaging eccentric exercise confers a protective effect against Max-Ecc, but the effect is attenuated between 1 and 2 weeks.
authors: Department of Physical Education, National Chiayi University, 85 Wenlong Village, Minsyong Township, Chiayi County 62103, Taiwan.
authors: Hsin-Lian
authors: HL
authors: Chen
authors: Kazunori
authors: K
authors: Nosaka
authors: Trevor C
authors: TC
authors: Chen
references: J Sci Med Sport. 2008 Jun;11(3):291-8
references: 17707693
references: Int J Sport Nutr Exerc Metab. 2006 Dec;16(6):620-35
references: 17342883
references: J Strength Cond Res. 2006 Feb;20(1):108-16
references: 16503669
references: Med Sci Sports Exerc. 2001 May;33(5):783-90
references: 11323549
references: Med Sci Sports Exerc. 2002 May;34(5):798-805
references: 11984298
references: Histochem Cell Biol. 2004 Mar;121(3):219-27
references: 14991331
references: Am J Sports Med. 2006 Jun;34(6):1000-7
references: 16476913
references: Am J Physiol Regul Integr Comp Physiol. 2001 Jul;281(1):R155-61
references: 11404289
references: J Physiol. 2001 Dec 1;537(Pt 2):333-45
references: 11731568
references: Scand J Med Sci Sports. 2003 Apr;13(2):88-97
references: 12641640
references: Med Sci Sports Exerc. 2008 Sep;40(9):1605-15
references: 18685531
references: J Sports Sci. 1997 Oct;15(5):477-83
references: 9386205
references: J Physiol. 2007 Aug 15;583(Pt 1):365-80
references: 17584833
references: Med Sci Sports Exerc. 2011 Mar;43(3):491-500
references: 20689450
references: J Strength Cond Res. 2002 Feb;16(1):117-22
references: 11834116
references: Eur J Appl Physiol. 2004 Oct;93(1-2):237-44
references: 15293054
references: Eur J Appl Physiol. 2009 May;106(2):267-75
references: 19263073
references: Eur J Appl Physiol. 2001 Jul;85(1-2):34-40
references: 11513318
references: Am J Physiol Regul Integr Comp Physiol. 2002 Oct;283(4):R958-63
references: 12228066
references: J Physiol. 2004 Nov 15;561(Pt 1):233-44
references: 15331678
references: Med Sci Sports Exerc. 1992 May;24(5):512-20
references: 1569847
references: Med Sci Sports Exerc. 2010 Jan;42(1):75-85
references: 20010127
references: J Appl Physiol (1985). 2007 Mar;102(3):992-9
references: 17138839
references: Med Sci Sports Exerc. 2010 May;42(5):1004-12
references: 19997007
references: Med Sci Sports Exerc. 2001 Sep;33(9):1490-5
references: 11528337
references: Can J Appl Physiol. 2005 Oct;30(5):529-42
references: 16293902
references: Med Sci Sports Exerc. 1996 Aug;28(8):953-61
references: 8871903
references: J Appl Physiol (1985). 1995 Mar;78(3):1065-9
references: 7775299