The repeated bout effect of reduced-load eccentric exercise on elbow flexor muscle damage

2001 ◽  
Vol 85 (1-2) ◽  
pp. 34-40 ◽  
Author(s):  
K. Nosaka ◽  
K. Sakamoto ◽  
M. Newton ◽  
P. Sacco
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.


2010 ◽  
Vol 35 (4) ◽  
pp. 534-540 ◽  
Author(s):  
Renato Barroso ◽  
Hamilton Roschel ◽  
Carlos Ugrinowitsch ◽  
Rubens Araújo ◽  
Kazunori Nosaka ◽  
...  

Eccentric exercise induces muscle damage, but controversy exists concerning the effect of contraction velocity on the magnitude of muscle damage, and little is known about the effect of contraction velocity on the repeated-bout effect. This study examined slow (60°·s–1) and fast (180°·s–1) velocity eccentric exercises for changes in indirect markers of muscle damage following 3 exercise bouts that were performed every 2 weeks. Fifteen young men were divided into 2 groups based on the velocity of eccentric exercise: 7 in the Ecc60 (60°·s–1) group, and 8 in the Ecc180 (180°·s–1) group. The exercise consisted of 30 maximal eccentric contractions of the elbow flexors at each velocity, in which the elbow joint was forcibly extended from 60° to 180° (full extension) on an isokinetic dynamometer. Changes in maximal voluntary isometric contraction strength, range of motion, muscle soreness, and plasma creatine kinase activity before and for 4 days after the exercise were compared in the 2 groups using a mixed-model analysis (group × bout × time). No significant differences between groups were evident for changes in any variables following exercise bouts; however, the changes were significantly smaller (p < 0.05) after the second and third bouts than after the first bout. These results indicate that the contraction velocity does not influence muscle damage or the repeated-bout effect.


2015 ◽  
Vol 3 (12) ◽  
pp. e12648 ◽  
Author(s):  
Nikos V. Margaritelis ◽  
Anastasios A. Theodorou ◽  
Vasilios Baltzopoulos ◽  
Constantinos N. Maganaris ◽  
Vassilis Paschalis ◽  
...  

2012 ◽  
Vol 37 (6) ◽  
pp. 1038-1046 ◽  
Author(s):  
Tomas Venckunas ◽  
Albertas Skurvydas ◽  
Marius Brazaitis ◽  
Sigitas Kamandulis ◽  
Audrius Snieckus ◽  
...  

Alpha-actinin-3 (ACTN3) is an integral part of the Z line of the sarcomere. The ACTN3 R577X (rs1815739) polymorphism determines the presence or absence of functional ACTN3, which may influence the extent of exercise-induced muscle damage. This study aimed to compare the impact of, and recovery from, muscle-damaging eccentric exercise on subjects with or without functional ACTN3. Seventeen young men (20–33 years old), homozygous for the R (n = 9) or X (n = 8) alleles, performed two bouts of stretch–shortening exercise (50 drop jumps) two weeks apart. Muscle soreness, plasma creatine kinase (CK) activity, jump height, maximal voluntary isometric torque (MVC), peak concentric isokinetic torque (IT), and electrically stimulated knee extension torques at 20 and 100 Hz were measured at baseline and at a number of time points up to 14 days after each bout. There were no significant baseline differences between the groups. However, significant time point × genotype interactions were observed for MVC (p = 0.021) and IT (p = 0.011) for the immediate effect of eccentric exercise in bout 1. The RR group showed greater voluntary force decrements (RR vs. XX: MVC, –33.3% vs. –24.5%; IT, –35.9% vs. –23.2%) and slower recovery. A repeated-bout effect was clearly observed, but there were no differences by genotype group. The ACTN3 genotype modulates the response of muscle function to plyometric jumping exercise, although the differences are modest. The ACTN3 genotype does not influence the clearly observed repeated-bout effect; however, XX homozygotes recover baseline voluntary torque values faster and thus may be able to undertake more frequent training sesssions.


2015 ◽  
Vol 308 (10) ◽  
pp. R879-R886 ◽  
Author(s):  
Wing Yin Lau ◽  
Anthony J. Blazevich ◽  
Michael J. Newton ◽  
Sam Shi Xuan Wu ◽  
Kazunori Nosaka

This study investigated biceps brachii distal myotendinous junction (MTJ) displacement during maximal eccentric elbow flexor contractions to test the hypothesis that muscle length change would be smaller (less MTJ displacement) during the second than the first exercise bout. Ten untrained men performed two eccentric exercise bouts (ECC1 and ECC2) with the same arm consisting of 10 sets of six maximal isokinetic (60°/s) eccentric elbow flexor contractions separated by 4 wk. Biceps brachii distal MTJ displacement was assessed using B-mode ultrasonography, and changes in the displacement (muscle length change) from the start to the end of each contraction during each set and over 10 sets were compared between bouts by two-way repeated-measures ANOVA. Several indirect muscle damage markers were also measured and compared between bouts by two-way repeated-measures ANOVA. The magnitude of MTJ displacement (average of six contractions) increased from set 1 (8.2 ± 4.7 mm) to set 10 (16.4 ± 4.7 mm) during ECC1 ( P < 0.05), but no significant changes over sets were evident during ECC2 ( set 1: 8.5 ± 4.0 mm; set 10: 9.3 ± 3.1 mm). Changes in maximal voluntary isometric contraction strength, range of motion, muscle thickness, ultrasound echo intensity, serum creatine kinase activity, and muscle soreness (visual analog scale) were smaller ( P < 0.05) following ECC2 than ECC1, showing less damage in the repeated bout. These results indicate that the magnitude of muscle lengthening was less during the second than the first eccentric exercise bout, which appears to be a mechanism underpinning the repeated-bout effect.


2018 ◽  
Vol 8 ◽  
Author(s):  
Ming-Ju Lin ◽  
Kazunori Nosaka ◽  
Chih-Chiao Ho ◽  
Hsin-Lian Chen ◽  
Kuo-Wei Tseng ◽  
...  

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