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Alterations in sarcoplasmic reticulum function in female vastus lateralis with eccentric exercise.
Molecular and Cellular Biochemistry
|March 8, 2000
Summary
Eccentric exercise impairs sarcoplasmic reticulum (SR) Ca2+ uptake for extended periods, even after muscle force recovers. This altered SR function is not linked to changes in Ca2+-ATPase activity.
Area of Science:
- Exercise Physiology
- Muscle Biology
- Cellular Physiology
Background:
- Eccentric exercise is known to cause muscle damage and force deficits.
- The role of sarcoplasmic reticulum (SR) Ca2+ handling in eccentric exercise-induced alterations is not fully understood.
Purpose of the Study:
- To investigate changes in SR Ca2+ sequestration function and Ca2+-ATPase activity following eccentric exercise.
- To correlate these changes with alterations in muscle force output during recovery.
Main Methods:
- Eight untrained females performed 60 minutes of eccentric cycling.
- Vastus lateralis muscle biopsies were collected before, after, and during recovery (days 2, 6, 14).
- SR Ca2+ uptake and Ca2+-ATPase activity were measured, alongside force output.
Main Results:
- SR Ca2+ uptake was depressed by day 2 post-exercise and remained altered throughout recovery.
- Ca2+-ATPase activity initially increased post-exercise, returning to baseline by day 6.
- Force output decreased immediately post-exercise but recovered by day 2, independent of SR Ca2+ uptake changes.
Conclusions:
- Prolonged alterations in SR Ca2+ sequestration occur after eccentric exercise.
- These SR function changes are not directly related to Ca2+-ATPase activity or immediate force recovery.