Effects of a second bout of maximal eccentric exercise on muscle damage and electromyographic activity

Research output: Contribution to journalArticle

68 Citations (Scopus)

Abstract

This study examined whether a second bout of maximal eccentric exercise performed 3 days after the first exercise bout would produce further changes in muscle damage and electromyographic activity (EMG). Male students (n = 26) were randomly assigned to experimental 70 (EX70; n = 9), experimental 30 (EX30; n = 8), and control (CON; n = 9) groups. The initial exercise was 30 maximal voluntary isokinetic eccentric contractions (MAX1) on non-dominant elbow flexors at 60° s-1 (1.05 rad s-1). The EX70 and EX30 groups performed a second bout of 70 and 30 eccentric contractions (MAX2), respectively, 3 days after MAX1. Upper arm circumference, range of motion, strength, integrated EMG (IEMG), and mean power frequency (MPF) were measured before, immediately after, and once a day for 9 days after MAX1. Plasma creatine kinase (CK) activity and muscle soreness were assessed before and for 9 days after MAX1. Total work, work per contraction, IEMG, and MPF were also recorded during MAX1 and MAX2. All indicators of muscle damage changed following MAX1 for each group (P<0.05), but no indicators of additional damage (P>0.05) were apparent after MAX2 for either the EX70 or EX30 groups. IEMG (P = 0.03) and MPF (P = 0.04) were lower for MAX2 compared with MAX1 for both the EX30 and EX70 groups. It is concluded that performing a second bout of eccentric exercise with damaged muscles 3 days after the initial bout does not produce further damage or retard recovery, even when the second bout of exercise is more strenuous. EMG findings were consistent with reduced activation of fast-twitch motor units during the second eccentric bout. These results may be interpreted as evidence of a neural protective mechanism.

Original languageEnglish
Pages (from-to)115-121
Number of pages7
JournalEuropean Journal of Applied Physiology
Volume89
Issue number2
DOIs
Publication statusPublished - 2003 Jan 1

Fingerprint

Exercise
Muscles
Myalgia
Creatine Kinase
Elbow
Articular Range of Motion
Arm
Students
Power (Psychology)

Keywords

  • Elbow flexors
  • Integrated electromyographic activity
  • Mean power frequency
  • Repeated bout effect

ASJC Scopus subject areas

  • Orthopedics and Sports Medicine
  • Public Health, Environmental and Occupational Health
  • Physiology (medical)

Cite this

@article{084f6719cd494f29aeaee1bcc45dc515,
title = "Effects of a second bout of maximal eccentric exercise on muscle damage and electromyographic activity",
abstract = "This study examined whether a second bout of maximal eccentric exercise performed 3 days after the first exercise bout would produce further changes in muscle damage and electromyographic activity (EMG). Male students (n = 26) were randomly assigned to experimental 70 (EX70; n = 9), experimental 30 (EX30; n = 8), and control (CON; n = 9) groups. The initial exercise was 30 maximal voluntary isokinetic eccentric contractions (MAX1) on non-dominant elbow flexors at 60° s-1 (1.05 rad s-1). The EX70 and EX30 groups performed a second bout of 70 and 30 eccentric contractions (MAX2), respectively, 3 days after MAX1. Upper arm circumference, range of motion, strength, integrated EMG (IEMG), and mean power frequency (MPF) were measured before, immediately after, and once a day for 9 days after MAX1. Plasma creatine kinase (CK) activity and muscle soreness were assessed before and for 9 days after MAX1. Total work, work per contraction, IEMG, and MPF were also recorded during MAX1 and MAX2. All indicators of muscle damage changed following MAX1 for each group (P<0.05), but no indicators of additional damage (P>0.05) were apparent after MAX2 for either the EX70 or EX30 groups. IEMG (P = 0.03) and MPF (P = 0.04) were lower for MAX2 compared with MAX1 for both the EX30 and EX70 groups. It is concluded that performing a second bout of eccentric exercise with damaged muscles 3 days after the initial bout does not produce further damage or retard recovery, even when the second bout of exercise is more strenuous. EMG findings were consistent with reduced activation of fast-twitch motor units during the second eccentric bout. These results may be interpreted as evidence of a neural protective mechanism.",
keywords = "Elbow flexors, Integrated electromyographic activity, Mean power frequency, Repeated bout effect",
author = "Chung-Ching Chen",
year = "2003",
month = "1",
day = "1",
doi = "10.1007/s00421-002-0791-1",
language = "English",
volume = "89",
pages = "115--121",
journal = "European Journal of Applied Physiology",
issn = "1439-6319",
publisher = "Springer Verlag",
number = "2",

}

TY - JOUR

T1 - Effects of a second bout of maximal eccentric exercise on muscle damage and electromyographic activity

AU - Chen, Chung-Ching

PY - 2003/1/1

Y1 - 2003/1/1

N2 - This study examined whether a second bout of maximal eccentric exercise performed 3 days after the first exercise bout would produce further changes in muscle damage and electromyographic activity (EMG). Male students (n = 26) were randomly assigned to experimental 70 (EX70; n = 9), experimental 30 (EX30; n = 8), and control (CON; n = 9) groups. The initial exercise was 30 maximal voluntary isokinetic eccentric contractions (MAX1) on non-dominant elbow flexors at 60° s-1 (1.05 rad s-1). The EX70 and EX30 groups performed a second bout of 70 and 30 eccentric contractions (MAX2), respectively, 3 days after MAX1. Upper arm circumference, range of motion, strength, integrated EMG (IEMG), and mean power frequency (MPF) were measured before, immediately after, and once a day for 9 days after MAX1. Plasma creatine kinase (CK) activity and muscle soreness were assessed before and for 9 days after MAX1. Total work, work per contraction, IEMG, and MPF were also recorded during MAX1 and MAX2. All indicators of muscle damage changed following MAX1 for each group (P<0.05), but no indicators of additional damage (P>0.05) were apparent after MAX2 for either the EX70 or EX30 groups. IEMG (P = 0.03) and MPF (P = 0.04) were lower for MAX2 compared with MAX1 for both the EX30 and EX70 groups. It is concluded that performing a second bout of eccentric exercise with damaged muscles 3 days after the initial bout does not produce further damage or retard recovery, even when the second bout of exercise is more strenuous. EMG findings were consistent with reduced activation of fast-twitch motor units during the second eccentric bout. These results may be interpreted as evidence of a neural protective mechanism.

AB - This study examined whether a second bout of maximal eccentric exercise performed 3 days after the first exercise bout would produce further changes in muscle damage and electromyographic activity (EMG). Male students (n = 26) were randomly assigned to experimental 70 (EX70; n = 9), experimental 30 (EX30; n = 8), and control (CON; n = 9) groups. The initial exercise was 30 maximal voluntary isokinetic eccentric contractions (MAX1) on non-dominant elbow flexors at 60° s-1 (1.05 rad s-1). The EX70 and EX30 groups performed a second bout of 70 and 30 eccentric contractions (MAX2), respectively, 3 days after MAX1. Upper arm circumference, range of motion, strength, integrated EMG (IEMG), and mean power frequency (MPF) were measured before, immediately after, and once a day for 9 days after MAX1. Plasma creatine kinase (CK) activity and muscle soreness were assessed before and for 9 days after MAX1. Total work, work per contraction, IEMG, and MPF were also recorded during MAX1 and MAX2. All indicators of muscle damage changed following MAX1 for each group (P<0.05), but no indicators of additional damage (P>0.05) were apparent after MAX2 for either the EX70 or EX30 groups. IEMG (P = 0.03) and MPF (P = 0.04) were lower for MAX2 compared with MAX1 for both the EX30 and EX70 groups. It is concluded that performing a second bout of eccentric exercise with damaged muscles 3 days after the initial bout does not produce further damage or retard recovery, even when the second bout of exercise is more strenuous. EMG findings were consistent with reduced activation of fast-twitch motor units during the second eccentric bout. These results may be interpreted as evidence of a neural protective mechanism.

KW - Elbow flexors

KW - Integrated electromyographic activity

KW - Mean power frequency

KW - Repeated bout effect

UR - http://www.scopus.com/inward/record.url?scp=0038546914&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0038546914&partnerID=8YFLogxK

U2 - 10.1007/s00421-002-0791-1

DO - 10.1007/s00421-002-0791-1

M3 - Article

VL - 89

SP - 115

EP - 121

JO - European Journal of Applied Physiology

JF - European Journal of Applied Physiology

SN - 1439-6319

IS - 2

ER -