Mitochondria-targeted antioxidant supplementation does not affect muscle soreness or recovery of maximal voluntary isometric contraction force following muscle-damaging exercise in untrained men: a randomised clinical trial

Palmitoylethanolamide Does Not Affect Recovery from Exercise-Induced Muscle Damage in Healthy Males

INTRODUCTION

Strenuous eccentric exercise (EE) induces microstructural muscle damage, which decreases muscle performance. Palmitoylethanolamide (PEA) exerts analgesic and anti-inflammatory effects in clinical pain conditions and preclinical models of experimentally induced inflammation. This might hold clues for improved recovery from EE. Therefore, the current study evaluates the effect of PEA supplementation on functional and molecular responses to a single EE bout.

METHODS

Eleven healthy male participants were included in a double-blind crossover study in which they received PEA (350 mg Levagen+) or placebo (maltodextrin) supplements, in a randomized order. In each experimental condition, participants performed an acute bout of EE (24 × 10 eccentric contractions of the knee extensors on an isokinetic dynamometer). At baseline, 24 (D1), 48 (D2), 72 (D3), and 120 h (D5) following EE, maximal voluntary contraction and jump height were measured. Blood samples were collected at baseline and on D1-D5, and muscle biopsies were collected at baseline and on D2. Perceived muscle soreness, sleep quality, and food intake were recorded daily.

RESULTS

Muscle strength and jump height decreased following EE (up to ~40% and ~17%, respectively; Ptime < 0.05) in both conditions. This drop was accompanied by an increase in plasma creatine kinase and perceived muscle soreness ( Ptime < 0.05). Furthermore, EE, but not PEA, increased the expression of the myogenic marker Pax7 and of the catabolic markers p-FoxO1-3a, p62, and LC3BII/I ( Ptime < 0.05).

CONCLUSIONS

PEA supplementation does not improve muscle soreness, muscle strength, and jump performance following a single EE bout. In addition, PEA supplementation had no effect on local or systemic markers of muscle damage, catabolism, or regeneration.

Effects of Mitoquinone (MitoQ) Supplementation on Aerobic Exercise Performance and Oxidative Damage: A Systematic Review and Meta-analysis

BACKGROUND

Contracting skeletal muscle produces reactive oxygen species (ROS) originating from both mitochondrial and cytosolic sources. The use of non-specific antioxidants, such as vitamins C and E, during exercise has produced inconsistent results in terms of exercise performance. Consequently, the effects of the mitochondrial-targeted coenzyme Q10, named Mitoquinone (MitoQ) on exercise responses are currently under investigation.

METHODS

In this study, we conducted a meta-analysis to quantitatively synthesize research assessing the impact of MitoQ on aerobic endurance performance and exercise-induced oxidative damage. PubMed, Web of Science, and SCOPUS databases were used to select articles from inception to January 16th of 2024. Inclusion criteria were MitoQ supplementation must be compared with a placebo group, showing acute exercise responses in both; for crossover designs, at least 14 d of washout was needed, and exercise training can be concomitant to MitoQ or placebo supplementation if the study meets the other inclusion criteria points. The risk of bias was evaluated through the Critical Appraisal Checklist (JBI).

RESULTS

We identified eight studies encompassing a total sample size of 188 subjects. Our findings indicate that MitoQ supplementation effectively reduces exercise-induced oxidative damage (SMD: -1.33; 95% CI: -2.24 to -0.43). Furthermore, our findings indicate that acute and/or chronic MitoQ supplementation does not improve endurance exercise performance (SMD: -0.50; 95% CI: -1.39 to 0.40) despite reducing exercise-induced oxidative stress. Notably, our sensitivity analysis reveals that MitoQ may benefit subjects with peripheral artery disease (PAD) in improving exercise tolerance.

CONCLUSION

While MitoQ effectively reduces exercise-induced oxidative damage, no evidence suggests that aerobic exercise performance is enhanced by either acute or chronic MitoQ supplementation. However, acute MitoQ supplementation may improve exercise tolerance in subjects with PAD. Future research should investigate whether MitoQ supplementation concurrent with exercise training (e.g., 4-16 weeks) alters adaptations induced by exercise alone and using different doses.

Astragalosides Supplementation Enhances Intrinsic Muscle Repair Capacity Following Eccentric Exercise-Induced Injury

Astragalosides have been shown to enhance endurance exercise capacity in vivo and promote muscular hypertrophy in vitro. However, it remains unknown whether astragalosides supplementation can alter inflammatory response and enhance muscle recovery after damage in humans. We therefore aimed to evaluate the effect of astragalosides supplementation on muscle's intrinsic capacity to regenerate and repair itself after exercise-induced damage. Using a randomized double-blind placebo-controlled cross-over design, eleven male participants underwent 7 days of astragalosides supplementation (in total containing 4 mg of astragalosides per day) or a placebo control, following an eccentric exercise protocol. Serum blood samples and variables related to muscle function were collected prior to and immediately following the muscle damage protocol and also at 2 h, and 1, 2, 3, 5, and 7 days of the recovery period, to assess the pro-inflammatory cytokine response, the secretion of muscle regenerative factors, and muscular strength. Astragalosides supplementation reduced biomarkers of skeletal muscle damage (serum CK, LDH, and Mb), when compared to the placebo, at 1, 2, and 3 days following the muscle damage protocol. Astragalosides supplementation suppressed the secretion of IL-6 and TNF-α, whilst increasing the release of IGF-1 during the initial stages of muscle recovery. Furthermore, following astragaloside supplementation, muscular strength returned to baseline 2 days earlier than the placebo. Astragalosides supplementation shortens the duration of inflammation, enhances the regeneration process and restores muscle strength following eccentric exercise-induced injury.