Quadriceps concentric and eccentric exercise 1: Changes in contractile and electrical activity following eccentric and concentric exercise

Hamlin, Michael J. and Quigley, Brian M. (2001) Quadriceps concentric and eccentric exercise 1: Changes in contractile and electrical activity following eccentric and concentric exercise. Journal of Science and Medicine In Sport, 4 1: 88-103. doi:10.1016/S1440-2440(01)80011-6


Author Hamlin, Michael J.
Quigley, Brian M.
Title Quadriceps concentric and eccentric exercise 1: Changes in contractile and electrical activity following eccentric and concentric exercise
Journal name Journal of Science and Medicine In Sport   Check publisher's open access policy
ISSN 1440-2440
Publication date 2001
Sub-type Article (original research)
DOI 10.1016/S1440-2440(01)80011-6
Volume 4
Issue 1
Start page 88
End page 103
Total pages 16
Editor B. Abernethy
Place of publication Belconnen, ACT
Publisher Sports Medicine Australia
Collection year 2002
Language eng
Subject CX
321405 Sports Medicine
780199 Other
Abstract The purpose of this study was to determine whether or not losses of strength or endurance following eccentric and concentric exercise are associated with reduced excitation. The effects of eccentric and concentric work on maximal voluntary isometric contraction (MVC) and surface electromyogram (EMG) of the quadriceps were studied in 10 healthy male subjects following bench-stepping for 20 min with a constant leading leg. Prior to stepping and at 0, 0.25, 0.50, 0.75, 1, 3. 24 and 48 h afterwards the subjects performed a 30 s leg extension MVC with each leg during which the isometric force and the root mean square voltage of the EMG were recorded. In the eccentrically exercised muscles (ECC), MVC0-3 (force during the first 3 s of contraction) fen immediately after the bench-stepping exercise to 88 +/- 2% (mean SE) of the pre-exercise value and remained significantly lower than the concentrically exercised muscles (p < 0.05). The muscle weakness in the ECC could not be attributed to central fatigue as surface EMG amplitude at MVC0-3 increased during the recovery period. Muscle weakness after eccentric exercise appears to be due to contractile failure, which is not associated with a reduction in excitation as assessed by surface EMG. Muscular fatigue over 30 s did not change in the two muscle groups after exercise (p = 0.79), indicating that the ECC were weaker but not more fatiguable after exercise.
Keyword Sport Sciences
Induced Muscle Damage
Sarcoplasmic-reticulum Function
Isometric Force-time
Skeletal-muscle
Ultrastructural-changes
Fiber Characteristics
Relaxation-time
Negative Work
Fatigue
Soreness
Q-Index Code CX

Document type: Journal Article
Sub-type: Article (original research)
Collection: School of Human Movement and Nutrition Sciences Publications
 
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Created: Tue, 14 Aug 2007, 17:59:00 EST