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Updated: Aug 7, 2026
14:10
Isometric and Eccentric Force Generation Assessment of Skeletal Muscles Isolated from Murine Models of Muscular Dystrophies
Published on: January 31, 2013
Attenuation of protective effect against eccentric exercise-induced muscle damage
Kazunori Nosaka1, Michael J Newton, Paul Sacco
1School of Exercise, Biomedical and Health Sciences, Edith Cowan University, Joondalup, WA 6027, Australia.
Summary
The protective effect of eccentric exercise diminishes over time. Increasing the interval between exercise bouts to 8 or 12 weeks reduced this protective effect, particularly for muscle strength and markers of muscle damage.
Area of Science:
- Exercise Physiology
- Muscle Adaptation
- Sports Science
Background:
- Eccentric exercise, characterized by muscle lengthening under tension, induces muscle damage but also confers a protective effect against subsequent exercise bouts.
- The duration of this protective effect, known as the repeated bout effect, is not fully understood, especially when intervals between exercise sessions are extended.
Purpose of the Study:
- To investigate the impact of extended recovery intervals (4, 8, and 12 weeks) on the protective effect of a single bout of eccentric exercise.
- To determine how different time intervals influence various physiological and perceptual measures of muscle damage and adaptation following eccentric exercise.
Main Methods:
- Thirty healthy young men participated in two bouts of 12 maximal eccentric elbow flexor actions.
- Participants were divided into three groups with intervals of 4, 8, or 12 weeks between exercise bouts.
- Measurements included maximal isometric strength, joint angles, range of motion, arm circumference, muscle soreness, plasma creatine kinase (CK), and myoglobin (Mb).
Main Results:
- No significant differences in responses were observed after the first exercise bout across all groups.
- A significantly smaller response to the second bout was observed in all measured variables at 4 and 8 weeks compared to the first bout.
- At 12 weeks, the protective effect was attenuated, with significantly smaller responses only observed for strength, muscle soreness, CK, and Mb.
Conclusions:
- The protective effect of eccentric exercise is partially attenuated after 8 weeks.
- The protective effect significantly diminishes by 12 weeks, with varying degrees of attenuation across different physiological and perceptual measures.
- The underlying factors contributing to the repeated bout effect may differ depending on the specific measure and the time interval between exercise sessions.
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