Purpose: This study aimed to analyze the effect of resistance training (RT) performed until volitional failure with low, moderate, and high loads on muscle hypertrophy and muscle strength in healthy adults and to assess the possible participant-, design-, and training-related covariates that may affect the adaptations. Methods: Using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, MEDLINE, CINAHL, EMBASE, SPORTDiscus, and Web of Science databases were searched. Including only studies that performed sets to volitional failure, the effects of low- (>15 repetitions maximum (RM)), moderate- (9–15 RM), and high-load (≤8 RM) RTs were examined in healthy adults. Network meta-analysis was undertaken to calculate the standardized mean difference (SMD) between RT loads in overall and subgroup analyses involving studies deemed of high quality. Associations between participant-, design-, and training-related covariates with SMD were assessed by univariate and multivariate network meta-regression analyses. Results: Twenty-eight studies involving 747 healthy adults were included. Although no differences in muscle hypertrophy between RT loads were found in overall (P = 0.113–0.469) or subgroup analysis (P = 0.871–0.995), greater effects were observed in untrained participants (P = 0.033) and participants with some training background who undertook more RT sessions (P = 0.031–0.045). Muscle strength improvement was superior for both high-load and moderate-load compared with low-load RT in overall and subgroup analysis (SMD, 0.60–0.63 and 0.34–0.35, respectively; P < 0.001–0.003), with a nonsignificant but superior effect for high compared with moderate load (SMD, 0.26–0.28, P = 0.068). Conclusions: Although muscle hypertrophy improvements seem to be load independent, increases in muscle strength are superior in high-load RT programs. Untrained participants exhibit greater muscle hypertrophy, whereas undertaking more RT sessions provides superior gains in those with previous training experience.

Summary: To systematically review and analyze the effects of resistance‐based exercise programs on body composition, regional adiposity, and body weight in individuals with overweight/obesity across the lifespan. Using PRISMA guidelines, randomized controlled trials were searched in nine electronic databases up to December 2020. Meta‐analyses were performed using random‐effects model. One‐hundred sixteen articles describing 114 trials (n = 4184 participants) were included. Interventions involving resistance training and caloric restriction were the most effective for reducing body fat percentage (ES = −3.8%, 95% CI: −4.7 to −2.9%, p < 0.001) and whole‐body fat mass (ES = −5.3 kg, 95% CI: −7.2 to −3.5 kg, p < 0.001) compared with groups without intervention. Significant results were also observed following combined resistance and aerobic exercise (ES = −2.3% and −1.4 kg, p < 0.001) and resistance training alone (ES = −1.6% and −1.0 kg, p < 0.001) compared with no training controls. Resistance training alone was the most effective for increasing lean mass compared with no training controls (ES = 0.8 kg, 95% CI: 0.6 to 1.0 kg, p < 0.001), whereas lean mass was maintained following interventions involving resistance training and caloric restriction (ES = ~ − 0.3 kg, p = 0.550–0.727). Results were consistently observed across age and sex groups (p = 0.001–0.011). Reductions in regional adiposity and body weight measures were also observed following combined resistance and aerobic exercise and programs including caloric restriction (p < 0.001). In conclusion, this study provides evidence that resistance‐based exercise programs are effective and should be considered within any multicomponent therapy program when caloric restriction is utilized in individuals with overweight or obesity.

Purpose: Resistance exercise improves an array of treatment-related adverse effects in men with prostate cancer; however, the minimal dosage required is unknown. We systematically reviewed the resistance training effects in prostate cancer patients to determine the minimal dosage regarding the exercise components (type, duration, volume, and intensity) on body composition, physical function, muscle strength, cardiorespiratory fitness, body mass index, and prostate-specific antigen. Methods: Using PRISMA guidelines, MEDLINE, CINAHL, EMBASE, SPORTDiscus, and Web of Science databases were searched. Eligible randomized controlled trials examined prostate cancer patients undertaking resistance-based exercise programs during or after treatment. Meta-analysis was undertaken when more than three studies were included. Associations between mean differences and exercise components were tested by univariate and multivariate meta-regression analysis. Results: Twenty-three articles describing 21 trials and involving 1748 prostate cancer patients were included. Exercise improved fat mass (−1% in body fat and −0.6 kg in fat mass), lean mass (~0.5 kg in lean and appendicular lean mass), functional capacity (i.e., chair rise, 400-m test, 6-m fast walk, and stair climb tests), and fitness outcomes (i.e., V̇O_2peak and muscle strength) (P = 0.040–<0.001) with no change in body mass index or prostate-specific antigen (P = 0.440–0.735). Meta-regression indicated no association between exercise type, resistance training duration, weekly volume and intensity, and primary outcomes (P = 0.075–0.965). There was a significant association between exercise intensity and chest press muscle strength (favoring moderate intensity, P = 0.012), but not in other secondary outcomes. Conclusion: In untrained older men with prostate cancer initiating an exercise program, lower volume at moderate to high intensity is as effective as higher volume resistance training for enhancing body composition, functional capacity, and muscle strength in the short term. A low exercise dosage may help reduce barriers to exercise and enhance adherence.

Background: To systematically review and analyse the associations between fat and muscle mass measures with overall survival in men with prostate cancer. Methods: A systematic search was conducted in CINAHL, Cochrane Library, EMBASE, PubMed, and Web of Science databases from inception to December 2020, while abstracts from the American Society of Clinical Oncology (ASCO), Clinical Oncology Society of Australia (COSA), and the American College of Sports Medicine (ACSM) conferences were searched from 2014 to 2020. Eligible articles examined the association of body composition measures, such as fat mass (e.g., fat mass, visceral adipose tissue (VAT), subcutaneous adipose tissue (SAT), and VAT/SAT) and muscle mass measures, with overall survival in prostate cancer patients at any treatment stage. The primary endpoint was overall survival. Random-effect meta-analysis was conducted for studies reporting multivariable or univariable analysis assessing the associations of fat mass measures (i.e., fat mass, VAT, SAT, VAT/SAT) and muscle mass measures with overall survival. Results: Sixteen cohort studies that comprised 4807 men with prostate cancer were included. Total adiposity (hazard ratio (HR) 0.98, 95% CI: 0.75–1.28, p = 0.888) and VAT (HR 1.03, 95% CI: 0.74–1.43, p = 0.873) were not significantly associated with overall survival, while higher subcutaneous adipose tissue levels were associated with higher survival (HR 0.68, 95% CI: 0.54–0.84, p = 0.001). Greater mortality risk was found in patients with localised (HR 1.91, 95% CI: 1.40–2.62, p < 0.001) and advanced disease (HR 1.43, 95% CI: 1.07–1.92, p = 0.020) presenting with low levels of muscle mass compared to those presenting with high levels. Discussion: These results indicate that although overall adiposity should be cautiously interpreted in regards to survival, high muscle mass and SAT, and low VAT/SAT ratio values are associated with overall survival in men with prostate cancer.