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Changes in human muscle protein synthesis after resistance exercise
A Chesley1, J D MacDougall, M A Tarnopolsky
1Department of Physical Education, McMaster University, Hamilton, Ontario, Canada.
Journal of Applied Physiology (Bethesda, Md. : 1985)
|October 1, 1992
Summary
Heavy resistance exercise boosts muscle protein synthesis (MPS) in the biceps for up to 24 hours. This increase is driven by enhanced translational processes, not transcriptional changes.
Area of Science:
- Exercise Physiology
- Molecular Biology
- Sports Science
Background:
- Muscle protein synthesis (MPS) is crucial for muscle adaptation.
- Understanding the temporal response of MPS to resistance exercise is key for optimizing training protocols.
Purpose of the Study:
- To quantify the magnitude and time course of MPS changes following a single bout of resistance exercise.
- To investigate the underlying molecular mechanisms (transcriptional vs. translational) influencing MPS post-exercise.
Main Methods:
- Two groups of male subjects performed unilateral elbow flexor resistance exercise.
- Muscle biopsy samples were analyzed for L-[1-13C]leucine incorporation to measure MPS.
- RNA capacity and RNA activity were assessed to differentiate transcriptional and translational contributions.
Main Results:
- A significant elevation in biceps muscle protein synthesis was observed in the exercised arm compared to the control arm at both 4 and 24 hours post-exercise.
- RNA capacity remained unchanged, indicating no increase in the potential for protein synthesis.
- RNA activity was significantly elevated, suggesting enhanced translational efficiency.
Conclusions:
- A single session of heavy resistance exercise stimulates biceps MPS for at least 24 hours.
- The observed increase in MPS is primarily mediated by post-transcriptional events, specifically enhanced translational activity.