Changes in the mechanical and electromyographic output during isotonic and isometric exercise in men and women

Randy J. Schmitz, Brent L. Arnold, David H. Perrin, Kevin P. Granata, Glenn Gaesser, Bruce M. Gansneder

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

Purpose: The purpose of this study was to determine if surface electromyography (EMG) could be used to index fatigue during isotonic and maximal voluntary isometric contractions (MVIC) of the knee extensors in men and women. Methods: Ten males (age = 22.1 ± 3.3 yr, ht = 180.3 ± 5.5 cm, mass 78.7 ± 5.1 kg) and ten females (age = 23.9±4.6 yr, ht = 163.7.3±11.1 cm, mass 63.2±7.4 kg) underwent one isometric (120 s MVIC of the knee extensors) and one isotonic (120 maximal effort isotonic contractions at a resistance of 25% of the MVIC peak torque determined on the testing day) exercise session separated by at least 48 hrs. The EMG signal was collected from the vastus lateralis during both exercise protocols using standard EMG collection techniques. Average torque (AT) was calculated from each 3 s window of the 120 s MVIC, and the average peak power (APP) was calculated for every 3 consecutive contractions during the dynamic exercise. Results: Both the isometric and isotonic fatigue protocols resulted in significant (p < 0.05) decreases in AT and APP, respectively. During the isotonic exercise protocol, decreases in APP during contractions 31-54 were significantly greater (p < 0.05) for males than females. Time-amplitude domain processing of the EMG data demonstrated significant decreases in the root mean square amplitude during the course of isometric exercise (p < 0.05) but not during isotonic exercise (p > 0.05). A main effect for gender (p < 0.05) revealed larger EMG amplitude for females when compared to males during isotonic exercise. Conclusions: These results indicate that gender may be a factor in the development of dynamic fatigue and that EMG can index fatigue during a sustained MVIC.

Original languageEnglish (US)
Pages (from-to)119-127
Number of pages9
JournalIsokinetics and Exercise Science
Volume8
Issue number3
StatePublished - 2000
Externally publishedYes

Fingerprint

Isometric Contraction
Electromyography
Fatigue
Exercise
Torque
Knee
Isotonic Contraction
Quadriceps Muscle

Keywords

  • EMG
  • Fatigue
  • Muscle assessment
  • Power

ASJC Scopus subject areas

  • Rehabilitation
  • Physical Therapy, Sports Therapy and Rehabilitation
  • Orthopedics and Sports Medicine

Cite this

Schmitz, R. J., Arnold, B. L., Perrin, D. H., Granata, K. P., Gaesser, G., & Gansneder, B. M. (2000). Changes in the mechanical and electromyographic output during isotonic and isometric exercise in men and women. Isokinetics and Exercise Science, 8(3), 119-127.

Changes in the mechanical and electromyographic output during isotonic and isometric exercise in men and women. / Schmitz, Randy J.; Arnold, Brent L.; Perrin, David H.; Granata, Kevin P.; Gaesser, Glenn; Gansneder, Bruce M.

In: Isokinetics and Exercise Science, Vol. 8, No. 3, 2000, p. 119-127.

Research output: Contribution to journalArticle

Schmitz, RJ, Arnold, BL, Perrin, DH, Granata, KP, Gaesser, G & Gansneder, BM 2000, 'Changes in the mechanical and electromyographic output during isotonic and isometric exercise in men and women', Isokinetics and Exercise Science, vol. 8, no. 3, pp. 119-127.
Schmitz, Randy J. ; Arnold, Brent L. ; Perrin, David H. ; Granata, Kevin P. ; Gaesser, Glenn ; Gansneder, Bruce M. / Changes in the mechanical and electromyographic output during isotonic and isometric exercise in men and women. In: Isokinetics and Exercise Science. 2000 ; Vol. 8, No. 3. pp. 119-127.
@article{d786ce22ab2d480b8b2986977fbc8894,
title = "Changes in the mechanical and electromyographic output during isotonic and isometric exercise in men and women",
abstract = "Purpose: The purpose of this study was to determine if surface electromyography (EMG) could be used to index fatigue during isotonic and maximal voluntary isometric contractions (MVIC) of the knee extensors in men and women. Methods: Ten males (age = 22.1 ± 3.3 yr, ht = 180.3 ± 5.5 cm, mass 78.7 ± 5.1 kg) and ten females (age = 23.9±4.6 yr, ht = 163.7.3±11.1 cm, mass 63.2±7.4 kg) underwent one isometric (120 s MVIC of the knee extensors) and one isotonic (120 maximal effort isotonic contractions at a resistance of 25{\%} of the MVIC peak torque determined on the testing day) exercise session separated by at least 48 hrs. The EMG signal was collected from the vastus lateralis during both exercise protocols using standard EMG collection techniques. Average torque (AT) was calculated from each 3 s window of the 120 s MVIC, and the average peak power (APP) was calculated for every 3 consecutive contractions during the dynamic exercise. Results: Both the isometric and isotonic fatigue protocols resulted in significant (p < 0.05) decreases in AT and APP, respectively. During the isotonic exercise protocol, decreases in APP during contractions 31-54 were significantly greater (p < 0.05) for males than females. Time-amplitude domain processing of the EMG data demonstrated significant decreases in the root mean square amplitude during the course of isometric exercise (p < 0.05) but not during isotonic exercise (p > 0.05). A main effect for gender (p < 0.05) revealed larger EMG amplitude for females when compared to males during isotonic exercise. Conclusions: These results indicate that gender may be a factor in the development of dynamic fatigue and that EMG can index fatigue during a sustained MVIC.",
keywords = "EMG, Fatigue, Muscle assessment, Power",
author = "Schmitz, {Randy J.} and Arnold, {Brent L.} and Perrin, {David H.} and Granata, {Kevin P.} and Glenn Gaesser and Gansneder, {Bruce M.}",
year = "2000",
language = "English (US)",
volume = "8",
pages = "119--127",
journal = "Isokinetics and Exercise Science",
issn = "0959-3020",
publisher = "IOS Press",
number = "3",

}

TY - JOUR

T1 - Changes in the mechanical and electromyographic output during isotonic and isometric exercise in men and women

AU - Schmitz, Randy J.

AU - Arnold, Brent L.

AU - Perrin, David H.

AU - Granata, Kevin P.

AU - Gaesser, Glenn

AU - Gansneder, Bruce M.

PY - 2000

Y1 - 2000

N2 - Purpose: The purpose of this study was to determine if surface electromyography (EMG) could be used to index fatigue during isotonic and maximal voluntary isometric contractions (MVIC) of the knee extensors in men and women. Methods: Ten males (age = 22.1 ± 3.3 yr, ht = 180.3 ± 5.5 cm, mass 78.7 ± 5.1 kg) and ten females (age = 23.9±4.6 yr, ht = 163.7.3±11.1 cm, mass 63.2±7.4 kg) underwent one isometric (120 s MVIC of the knee extensors) and one isotonic (120 maximal effort isotonic contractions at a resistance of 25% of the MVIC peak torque determined on the testing day) exercise session separated by at least 48 hrs. The EMG signal was collected from the vastus lateralis during both exercise protocols using standard EMG collection techniques. Average torque (AT) was calculated from each 3 s window of the 120 s MVIC, and the average peak power (APP) was calculated for every 3 consecutive contractions during the dynamic exercise. Results: Both the isometric and isotonic fatigue protocols resulted in significant (p < 0.05) decreases in AT and APP, respectively. During the isotonic exercise protocol, decreases in APP during contractions 31-54 were significantly greater (p < 0.05) for males than females. Time-amplitude domain processing of the EMG data demonstrated significant decreases in the root mean square amplitude during the course of isometric exercise (p < 0.05) but not during isotonic exercise (p > 0.05). A main effect for gender (p < 0.05) revealed larger EMG amplitude for females when compared to males during isotonic exercise. Conclusions: These results indicate that gender may be a factor in the development of dynamic fatigue and that EMG can index fatigue during a sustained MVIC.

AB - Purpose: The purpose of this study was to determine if surface electromyography (EMG) could be used to index fatigue during isotonic and maximal voluntary isometric contractions (MVIC) of the knee extensors in men and women. Methods: Ten males (age = 22.1 ± 3.3 yr, ht = 180.3 ± 5.5 cm, mass 78.7 ± 5.1 kg) and ten females (age = 23.9±4.6 yr, ht = 163.7.3±11.1 cm, mass 63.2±7.4 kg) underwent one isometric (120 s MVIC of the knee extensors) and one isotonic (120 maximal effort isotonic contractions at a resistance of 25% of the MVIC peak torque determined on the testing day) exercise session separated by at least 48 hrs. The EMG signal was collected from the vastus lateralis during both exercise protocols using standard EMG collection techniques. Average torque (AT) was calculated from each 3 s window of the 120 s MVIC, and the average peak power (APP) was calculated for every 3 consecutive contractions during the dynamic exercise. Results: Both the isometric and isotonic fatigue protocols resulted in significant (p < 0.05) decreases in AT and APP, respectively. During the isotonic exercise protocol, decreases in APP during contractions 31-54 were significantly greater (p < 0.05) for males than females. Time-amplitude domain processing of the EMG data demonstrated significant decreases in the root mean square amplitude during the course of isometric exercise (p < 0.05) but not during isotonic exercise (p > 0.05). A main effect for gender (p < 0.05) revealed larger EMG amplitude for females when compared to males during isotonic exercise. Conclusions: These results indicate that gender may be a factor in the development of dynamic fatigue and that EMG can index fatigue during a sustained MVIC.

KW - EMG

KW - Fatigue

KW - Muscle assessment

KW - Power

UR - http://www.scopus.com/inward/record.url?scp=0033738519&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0033738519&partnerID=8YFLogxK

M3 - Article

AN - SCOPUS:0033738519

VL - 8

SP - 119

EP - 127

JO - Isokinetics and Exercise Science

JF - Isokinetics and Exercise Science

SN - 0959-3020

IS - 3

ER -