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Updated: Oct 11, 2025
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Induction and Assessment of Exertional Skeletal Muscle Damage in Humans
Published on: December 11, 2016
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Structural and pathological changes in the enthesis are influenced by the muscle contraction type during exercise
Kaichi Ozone1,2, Takanori Kokubun3, Kei Takahata1
1Department of Health and Social Services, Health and Social Services, Graduate School of Saitama Prefectural University, Koshigaya, Saitama, Japan.
Summary
Eccentric muscle contractions, not exercise volume, may drive sports-related enthesopathy. Slow-speed downhill running caused pathological changes, highlighting muscle contraction type
Area of Science:
- Sports Medicine
- Orthopedics
- Biomechanical Engineering
Background:
- Sports-related enthesopathy is linked to mechanical stress during exercise.
- Both exercise volume and muscle contraction type contribute to mechanical stress.
Purpose of the Study:
- To investigate the impact of muscle contraction type and exercise volume on enthesis.
- To differentiate the effects of mechanical stress from exercise amount versus contraction type.
Main Methods:
- Treadmill exercise in mice with varied speed and incline to alter muscle contraction type and load.
- Histological and microcomputer imaging analysis of muscle, enthesis fibrocartilage (FC), and bone.
- Molecular analysis of inflammation and cytokine-related factors in tendons.
Main Results:
- Increased exercise volume (Overuse group) showed no significant pathological changes compared to controls.
- Slow-speed downhill running (Misuse group) induced pathological enthesis changes despite low exercise volume.
- Eccentric muscle contractions appear to increase local mechanical stress more significantly than overall exercise volume.
Conclusions:
- Muscle contraction type, particularly eccentric contractions, may be a primary driver of sports-related enthesopathy.
- Enthesis fibrocartilage alterations are more sensitive to localized stress from specific muscle actions than generalized overuse.
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