The effects of exergames on muscle strength: A systematic review and meta-analysis

This systematic review and meta-analysis examined studies on the chronic effects of exergames on muscle strength in humans. PubMed, Scopus, CENTRAL, Web of Science, SciELO, Biblioteca Virtual em Saúde, and Google Scholar were searched, and manual searches of the reference lists of included studies and hand-searches on Physiotherapy Evidence Database and ResearchGate were conducted from inception to August 10, 2020. Randomized and non-randomized exergame intervention studies with or without a non-exercise group and/or a "usual care intervention group" (any other intervention that did not incorporate exergames), which evaluated muscle strength through direct measurements, were included. Forty-seven and 25 studies were included in the qualitative review and meta-analysis, respectively. The between-groups meta-analyses showed no significant differences between exergames and non-exercise control groups for handgrip strength in heathy/unhealthy middle-aged/older adults or knee extension maximum voluntary isometric contraction (MVIC) in healthy older adults. However, exergames provided a greater increase in handgrip strength, knee flexion MVIC, and elbow extension MVIC, but not knee extension MVIC or elbow flexion MVIC, in individuals with different health statuses when compared to usual care interventions. Also, there was a greater increase in handgrip strength in children with hemiplegic cerebral palsy favouring usual care plus exergames compared to usual care interventions. These results suggest that exergames may improve upper and lower limb muscle strength in individuals with different heath statuses compared to usual care interventions, but not muscle strength in middle age/older adults after accounting for random error. Also, exergames appear to be a useful tool for improving handgrip strength in children with hemiplegic cerebral palsy when added to usual care. However, as the exergame interventions were applied in different populations and there currently are many different approaches to perform exergames, future randomized controlled trials with high methodological quality and large sample sizes are needed to provide more compelling evidence in favour of a specific exergame protocol, or to elucidate exergame protocol design principles that appear to strongly influence outcomes.

Acute and chronic effects of Rhaponticum carthamoides and Rhodiola rosea extracts supplementation coupled to resistance exercise on muscle protein synthesis and mechanical power in rats

BACKGROUND

Owing to its strength-building and adaptogenic properties, Rhaponticum carthamoides (Rha) has been commonly used by elite Soviet and Russian athletes. Rhodiola rosea (Rho) is known to reduce physical and mental fatigue and improve endurance performance. However, the association of these two nutritional supplements with resistance exercise performance has never been tested. Resistance exercise is still the best way to stimulate protein synthesis and induce chronic muscle adaptations. The aim of this study was to investigate the acute and chronic effects of resistance exercise coupled with Rha and Rho supplementation on protein synthesis, muscle phenotype, and physical performance.

METHODS

For the acute study, fifty-six rats were assigned to either a trained control group or one of the groups treated with specific doses of Rha and/or Rho. Each rats performed a single bout of climbing resistance exercise. The supplements were administered immediately after exercise by oral gavage. Protein synthesis was measured via puromycin incorporation. For the chronic study, forty rats were assigned to either the control group or one of the groups treated with doses adjusted from the acute study results. The rats were trained five times per week for 4 weeks with the same bout of climbing resistance exercise with additionals loads. Rha + Rho supplement was administered immediately after each training by oral gavage.

RESULTS

The findings of the acute study indicated that Rha and Rha + Rho supplementation after resistance exercise stimulated protein synthesis more than resistance exercise alone (p < 0.05). After 4 weeks of training, the mean power performance was increased in the Rha + Rho and Rha-alone groups (p < 0.05) without any significant supplementation effect on muscle weight or fiber cross-sectional area. A tendency towards an increase in type I/ type II fiber ratio was observed in Rha/Rho-treated groups compared to that in the trained control group.

CONCLUSION

Rhodiola and Rhaponticum supplementation after resistance exercise could synergistically improve protein synthesis, muscle phenotype and physical performance.

A novel voluntary weightlifting model in mice promotes muscle adaptation and insulin sensitivity with simultaneous enhancement of autophagy and mTOR pathway

Our understanding of the molecular mechanisms underlying adaptations to resistance exercise remains elusive despite the significant biological and clinical relevance. We developed a novel voluntary mouse weightlifting model, which elicits squat-like activities against adjustable load during feeding, to investigate the resistance exercise-induced contractile and metabolic adaptations. RNAseq analysis revealed that a single bout of weightlifting induced significant transcriptome responses of genes that function in posttranslational modification, metabolism, and muscle differentiation in recruited skeletal muscles, which were confirmed by increased expression of fibroblast growth factor-inducible 14 (Fn14), Down syndrome critical region 1 (Dscr1) and Nuclear receptor subfamily 4, group A, member 3 (Nr4a3) genes. Long-term (8 weeks) voluntary weightlifting training resulted in significantly increases of muscle mass, protein synthesis (puromycin incorporation in SUnSET assay) and mTOR pathway protein expression (raptor, 4e-bp-1, and p70S6K proteins) along with enhanced muscle power (specific torque and contraction speed), but not endurance capacity, mitochondrial biogenesis, and fiber type transformation. Importantly, weightlifting training profound improved whole-body glucose clearance and skeletal muscle insulin sensitivity along with enhanced autophagy (increased LC3 and LC3-II/I ratio, and decreased p62/Sqstm1). These data suggest that resistance training in mice promotes muscle adaptation and insulin sensitivity with simultaneous enhancement of autophagy and mTOR pathway.