Muscle damage protection by low-intensity eccentric contractions remains for 2 weeks but not 3 weeks

2011 ◽  
Vol 112 (2) ◽  
pp. 555-565 ◽  
Author(s):  
Hsin-Lian Chen ◽  
Kazunori Nosaka ◽  
Trevor C. Chen
Author(s):  
Trevor C. Chen ◽  
Wei-Chin Tseng ◽  
Hsin-Lian Chen ◽  
Kuo-Wei Tseng ◽  
Tai-Ying Chou ◽  
...  

We investigated the effects of repeating 30 low-intensity eccentric contractions with a dumbbell corresponding to 10% maximal isometric strength (10%EC) on muscle strength and hypertrophy, and muscle damage after 30 maximal eccentric contractions of the elbow flexors (MaxEC). Young men were placed to one of three experimental groups that performed 10%EC either once, twice a week for four (eight bouts) or eight weeks (16 bouts) before MaxEC, or a control group that performed two bouts of MaxEC separated by two weeks (n=13/group). Repeating 16 bouts of 10%EC increased (P<0.05) maximal voluntary contraction strength (30±21%) and muscle thickness (4.2±2.3%) greater than eight bouts (16±4%, 1.9±1.3%). Changes in the muscle damage markers after MaxEC were smaller (P<0.05) for the experimental groups than the control group, and the magnitude of muscle damage protection was greater (P<0.05) after 16 (65±30%) than 8 bouts (55±33%), followed by one bout (34±27%). The protection by 16 bouts was similar (P=0.81) to that shown by the second MaxEC of the control group. These results showed that 10%EC produced potent muscle adaptation effects accumulatively and conferred muscle damage protection, but one bout of 10%EC was still effective for conferring approximately 20% of the protection of that by 16 bouts. Novelty bullets: ●Repeating low-intensity eccentric exercise induces large increases in muscle strength and hypertrophy. ●Low-intensity eccentric exercise protects muscle damage induced by maximal eccentric contractions, and the protection is reinforced by repeating it. ●These are especially beneficial for individuals who are frail and cannot tolerate high-intensity resistance training.


2017 ◽  
Vol 49 (5S) ◽  
pp. 948
Author(s):  
Trevor C. Chen ◽  
Ming-Ju Lin ◽  
Hsin-Lian Chen ◽  
Kazunori Nosaka

2015 ◽  
Vol 40 (10) ◽  
pp. 1004-1011 ◽  
Author(s):  
Min-Ju Lin ◽  
Trevor Chung-Ching Chen ◽  
Hsin-Lian Chen ◽  
Bo-Han Wu ◽  
Kazunori Nosaka

This study investigated the magnitude and duration of the protective effect of low-intensity eccentric contractions (LowEC) against damage induced by maximal eccentric contractions (MaxEC) of the knee flexors (KF) and extensors (KE). Young men were assigned to 8 experimental groups and 2 control groups (n = 13/group); the experimental groups performed LowEC of KF or KE 2 days (2d), 1 week (1wk), 2 weeks (2wk), or 3 weeks (3wk) before MaxEC, while the control groups performed MaxEC of KF or KE without LowEC. The 2d, 1wk, 2wk, and 3wk groups performed 30 LowEC of KF or 60 LowEC of KE with a load of 10% of maximal voluntary isometric contraction strength on a resistance-training machine, and all groups performed 30 MaxEC of KF or 60 MaxEC of KE on an isokinetic dynamometer. Several muscle damage markers were measured from before to 2 days after exercise (LowEC) or from before to 5 days after exercise (MaxEC). No significant changes in any variables were evident after LowEC. The changes in all variables after MaxEC were smaller (P < 0.05) for the 2d and 1wk groups (e.g., peak creatine kinase activity: 1002 ± 501 IU/L; peak muscle soreness: 13 ± 5 mm) than for the control group (peak creatine kinase activity: 3005 ± 983 IU/L; peak muscle soreness 28 ± 6 mm) for both KE and KF. There were no significant differences between the 2d and 1wk groups or among the 2wk, 3wk, and control groups. These results show that LowEC provided 30%–66% protection against damage induced by MaxEC of KF and KE, and the protective effect lasted 1 week.


2012 ◽  
Vol 113 (4) ◽  
pp. 1005-1015 ◽  
Author(s):  
Trevor C. Chen ◽  
Wei-Chin Tseng ◽  
Guan-Ling Huang ◽  
Hsin-Lian Chen ◽  
Kou-Wei Tseng ◽  
...  

2014 ◽  
Vol 101 (2) ◽  
pp. 150-157 ◽  
Author(s):  
Robert Thiebaud ◽  
J.P. Loenneke ◽  
C.A. Fahs ◽  
D. Kim ◽  
X. Ye ◽  
...  

2014 ◽  
Vol 46 ◽  
pp. 925
Author(s):  
Trevor C. Chen ◽  
Hsin-Lian Chen ◽  
Ming-Ju Lin ◽  
Kuan-Chieh Chen ◽  
Bo-Han Wu ◽  
...  

2018 ◽  
Vol 21 (10) ◽  
pp. 1068-1072 ◽  
Author(s):  
Trevor C. Chen ◽  
Ming-Ju Lin ◽  
Jian-Han Lai ◽  
Hsin-Lian Chen ◽  
Hui-I Yu ◽  
...  

Author(s):  
Avery Hinks ◽  
Adam Hess ◽  
Mathew I. B. Debenham ◽  
Jackey Chen ◽  
Nicole Mazara ◽  
...  

High intensity unaccustomed eccentric contractions result in weakness and power loss due to fatigue and muscle damage. Through the repeated bout effect (RBE), adaptations occur, then damage and weakness are attenuated following a subsequent bout. However, it is unclear whether the RBE protects peak power output. We investigated the influence of the RBE on power production and estimated fatigue- and damage-induced neuromuscular impairments following repeated high-intensity eccentric contractions. Twelve healthy adult males performed 5 sets of 30 maximal eccentric elbow flexions and repeated an identical bout 4 weeks later. Recovery was tracked over 7 days following both bouts. Reduced maximum voluntary isometric contraction torque, and increased serum creatine kinase and self-reported soreness indirectly inferred muscle damage. Peak isotonic power, time-dependent measures—rate of velocity development (RVD) and rate of torque development (RTD)—and several electrophysiological indices of neuromuscular function were assessed. The RBE protected peak power, with a protective index of 66% 24 hours after the second eccentric exercise bout. The protection of power also related to preserved RVD (R2=0.61, P<0.01) and RTD (R2=0.39, P<0.01). Furthermore, the RBE’s protection against muscle damage permitted the estimation of fatigue-associated neuromuscular performance decrements following eccentric exercise. Novelty Bullets • The repeated bout effect protects peak isotonic power. • Protection of peak power relates to preserved rates of torque and velocity development, but more so rate of velocity development. • The repeated bout effect has little influence on indices of neuromuscular fatigue.


2015 ◽  
Vol 3 (7) ◽  
pp. e12449 ◽  
Author(s):  
Mizuki Sudo ◽  
Soichi Ando ◽  
David C. Poole ◽  
Yutaka Kano

Sign in / Sign up

Export Citation Format

Share Document