Threshold Number Of Low-intensity Eccentric Contractions Of The Elbow Flexors To Induce Muscle Damage

2017 ◽  
Vol 49 (5S) ◽  
pp. 948
Author(s):  
Trevor C. Chen ◽  
Ming-Ju Lin ◽  
Hsin-Lian Chen ◽  
Kazunori Nosaka
Keyword(s):  
Muscle Damage ◽  
Eccentric Contractions ◽  
Elbow Flexors ◽  
Low Intensity

Striking muscle adaptations induced by volume-dependent repeated bouts of low-intensity eccentric exercise of the elbow flexors

2021 ◽  
Author(s):  
Trevor C. Chen ◽  
Wei-Chin Tseng ◽  
Hsin-Lian Chen ◽  
Kuo-Wei Tseng ◽  
Tai-Ying Chou ◽  
...  
Keyword(s):  
Muscle Strength ◽  
Muscle Damage ◽  
Eccentric Exercise ◽  
Voluntary Contraction ◽  
Eccentric Contractions ◽  
Control Group ◽  
Elbow Flexors ◽  
Muscle Adaptation ◽  
Low Intensity ◽  
Damage Protection

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.

Low-intensity eccentric contractions of the knee extensors and flexors protect against muscle damage

2015 ◽  
Vol 40 (10) ◽  
pp. 1004-1011 ◽  
Author(s):  
Min-Ju Lin ◽  
Trevor Chung-Ching Chen ◽  
Hsin-Lian Chen ◽  
Bo-Han Wu ◽  
Kazunori Nosaka
Keyword(s):  
Creatine Kinase ◽  
Protective Effect ◽  
Muscle Damage ◽  
Muscle Soreness ◽  
Kinase Activity ◽  
Creatine Kinase Activity ◽  
Eccentric Contractions ◽  
Control Group ◽  
Control Groups ◽  
Low Intensity

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.

Low-intensity eccentric contractions attenuate muscle damage induced by subsequent maximal eccentric exercise of the knee extensors in the elderly

2012 ◽  
Vol 113 (4) ◽  
pp. 1005-1015 ◽  
Author(s):  
Trevor C. Chen ◽  
Wei-Chin Tseng ◽  
Guan-Ling Huang ◽  
Hsin-Lian Chen ◽  
Kou-Wei Tseng ◽  
...  
Keyword(s):  
Muscle Damage ◽  
Eccentric Exercise ◽  
The Elderly ◽  
Eccentric Contractions ◽  
Knee Extensors ◽  
Low Intensity

Muscle damage after low-intensity eccentric contractions with blood flow restriction

2014 ◽  
Vol 101 (2) ◽  
pp. 150-157 ◽  
Author(s):  
Robert Thiebaud ◽  
J.P. Loenneke ◽  
C.A. Fahs ◽  
D. Kim ◽  
X. Ye ◽  
...  
Keyword(s):  
Blood Flow ◽  
Muscle Damage ◽  
Blood Flow Restriction ◽  
Eccentric Contractions ◽  
Flow Restriction ◽  
Low Intensity

scholarly journals Two maximal isometric contractions attenuate the magnitude of eccentric exercise-induced muscle damage

2012 ◽  
Vol 37 (4) ◽  
pp. 680-689 ◽  
Author(s):  
Hsin-Lian Chen ◽  
Kazunori Nosaka ◽  
Alan J. Pearce ◽  
Trevor C. Chen
Keyword(s):  
Muscle Damage ◽  
Eccentric Exercise ◽  
Muscle Soreness ◽  
Muscle Length ◽  
Peak Torque ◽  
Eccentric Contractions ◽  
Control Group ◽  
Isometric Contractions ◽  
Elbow Flexors ◽  
Exercise Induced

This study investigated whether maximal voluntary isometric contractions (MVC-ISO) would attenuate the magnitude of eccentric exercise-induced muscle damage. Young untrained men were placed into one of the two experimental groups or one control group (n = 13 per group). Subjects in the experimental groups performed either two or 10 MVC-ISO of the elbow flexors at a long muscle length (20° flexion) 2 days prior to 30 maximal isokinetic eccentric contractions of the elbow flexors. Subjects in the control group performed the eccentric contractions without MVC-ISO. No significant changes in maximal voluntary concentric contraction peak torque, peak torque angle, range of motion, upper arm circumference, plasma creatine kinase (CK) activity and myoglobin concentration, muscle soreness, and ultrasound echo intensity were evident after MVC-ISO. Changes in the variables following eccentric contractions were smaller (P < 0.05) for the 2 MVC-ISO group (e.g., peak torque loss at 5 days after exercise, 23% ± 3%; peak CK activity, 1964 ± 452 IU·L–1; peak muscle soreness, 46 ± 4 mm) or the 10 MVC-ISO group (13% ± 3%, 877 ± 198 IU·L–1, 30 ± 4 mm) compared with the control (34% ± 4%, 6192 ± 1747 IU·L–1, 66 ± 5 mm). The 10 MVC-ISO group showed smaller (P < 0.05) changes in all variables following eccentric contractions compared with the 2 MVC-ISO group. Therefore, two MVC-ISO conferred potent protective effects against muscle damage, whereas greater protective effect was induced by 10 MVC-ISO, which can be used as a strategy to minimize muscle damage.

Low-intensity Eccentric Contractions Attenuate Maximal Eccentric Contraction-induced Muscle Damage of the Knee Extensors

2014 ◽  
Vol 46 ◽  
pp. 925
Author(s):  
Trevor C. Chen ◽  
Hsin-Lian Chen ◽  
Ming-Ju Lin ◽  
Kuan-Chieh Chen ◽  
Bo-Han Wu ◽  
...  
Keyword(s):  
Muscle Damage ◽  
Eccentric Contraction ◽  
Eccentric Contractions ◽  
Knee Extensors ◽  
Low Intensity
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