Effects of Physical Exercise on MuRF-1/ Expression in Humans: A Systematic Review.

Background/objectives: Muscle-specific RING finger protein 1 (MuRF-1) is a pivotal regulator of muscle protein breakdown, an essential process for post-exercise muscle adaptation. This systematic review aimed to evaluate the effects of physical exercise on MuRF-1 expression in humans.

Methods: A literature search was conducted in PubMed, Scopus, Cochrane Library, Google Scholar, and Web of Science following the PRISMA guidelines. The search was limited to studies published from 1 January 2001 to 1 December 2024. The inclusion and exclusion criteria were defined using the PICOS strategy. Two investigators independently performed the study selection, data extraction, and assessment of methodological quality, with any disagreements resolved by a third investigator. The PEDro scale was used to evaluate the risk of bias.

Results: Forty-six studies met the eligibility criteria and were included. The findings evidenced that physical exercise significantly modulates MuRF-1 expression in humans. Resistance exercise induces transient increases, typically peaking between 1 and 4 h, whereas endurance exercise elicits similar responses within 40 min to 4 h post-exercise. Combined exercise protocols that include resistance and endurance exercises significantly increased MuRF-1 expression at 3 h post-exercise. The effects of physical exercise on MuRF-1 expression are influenced by factors such as exercise order, intensity, contraction mode, age, sex, and fitness level.

Conclusions: This systematic review shows that MuRF-1 expression is significantly modulated by physical exercise in humans and is sensitive to different exercise modalities. These findings suggest that this key protein involved in muscle protein breakdown and turnover is essential for exercise-induced adaptations, contributing to skeletal muscle recovery and remodeling after exercise.