Activation of satellite cells and the regeneration of human skeletal muscle are expedited by ingestion of nonsteroidal anti-inflammatory medication.

With this study we investigated the role of nonsteroidal anti-inflammatory drugs (NSAIDs) in human skeletal muscle regeneration. Young men ingested NSAID [1200 mg/d ibuprofen (IBU)] or placebo (PLA) daily for 2 wk before and 4 wk after an electrical stimulation-induced injury to the leg extensor muscles of one leg. Muscle biopsies were collected from the vastus lateralis muscles before and after stimulation (2.5 h and 2, 7, and 30 d) and were assessed for satellite cells and regeneration by immunohistochemistry and real-time RT-PCR, and we also measured telomere length. After injury, and compared with PLA, IBU was found to augment the proportion of ActiveNotch1(+) satellite cells at 2 d [IBU, 29 ± 3% vs. PLA, 19 ± 2% (means ± sem)], satellite cell content at 7 d [IBU, 0.16 ± 0.01 vs. PLA, 0.12 ± 0.01 (Pax7(+) cells/fiber)], and to expedite muscle repair at 30 d. The PLA group displayed a greater proportion of embryonic myosin(+) fibers and a residual ∼2-fold increase in mRNA levels of matrix proteins (all P < 0.05). Endomysial collagen was also elevated with PLA at 30 d. Minimum telomere length shortening was not observed. In conclusion, ingestion of NSAID has a potentiating effect on Notch activation of satellite cells and muscle remodeling during large-scale regeneration of injured human skeletal muscle.-Mackey, A. L., Rasmussen, L. K., Kadi, F., Schjerling, P., Helmark, I. C., Ponsot, E., Aagaard, P., Durigan, J. L. Q., Kjaer, M. Activation of satellite cells and the regeneration of human skeletal muscle are expedited by ingestion of nonsteroidal anti-inflammatory medication.

Effects of whole-body electromyostimulation on health indicators of older people: Systematic review and meta-analysis of randomized trials.

OBJECTIVE: to provide evidence for the effects of whole-body electromyostimulation (WB-EMS) on health-related outcomes compared to the effects of minimal or non-intervention for older people in the short/medium/long term. DATA SOURCES: seven databases (MEDLINE, Embase, CENTRAL, CINAHL, Scopus, SPORTDiscuss and Web of Science) were electronically searched in April 2020 and updated in March 2021. STUDY SELECTION: included studies were randomized controlled trials (RCTs) involving WB-EMS that assessed effects on health-related outcomes, risks and adverse events in older people (>60 years). DATA EXTRACTION: the following data were obtained: author and publication year, follow-up, detailed information of older characteristics, current parameters/intensity and outcomes. DATA SYNTHESIS: a random effects model was used with effect size reported as SMD. Statistical heterogeneity was assessed using the I2 test. RESULTS: 13 RCTs met the eligibility criteria. Meta-analysis found: large effects of WB-EMS on reducing sarcopenia Z-score (ES: 1.44[-2.02: 0.87] p= <.01) and improving isometric strength leg extensors (ES: 0.81[0.41: 1.21] p= <.01) at medium and long-term, respectively. Moderate effects of WB-EMS on improving handgrip strength (ES: 0.58[0.23: 0.92] p= <.01) and habitual gait speed (ES: 0.69[0.31: 1.07] p= <.01) at medium-term and improving appendicular skeletal muscle mass (ES:0.69 [0.30: 1.09] p= <.01) at long-term. Non-significant effect of WB-EMS on waist circumference (p = .17) and triglycerides (p = .20) at medium-term. Non-significant effects of WB-EMS on improving creatine kinase concentrations, C-reactive protein, and interleukin 6 at medium-term. CONCLUSIONS: This review provides further evidence for significant, moderate to large effect sizes of WB-EMS on sarcopenia, muscle mass and strength parameters, but not on waist circumference and triglycerides. SYSTEMATIC REVIEW REGISTRATION: PROSPERO database no. CRD42019134100.

Effects of neuromuscular electrical stimulation on torque and performance in recreational distance runners: A randomized controlled trial.

INTRODUCTION: Neuromuscular electrical stimulation (NMES) is used by athletes to improve muscle performance. However, evidence on the use of NMES in long distance runners is scarce. As such, this study aimed to evaluate the effects of NMES on the muscle torque and sports performance of long-distance recreational runners. METHODS: This was a blinded randomized controlled trial. Data from 30 volunteers were analyzed. Participants were randomly allocated to an experimental (n = 15) or control group (n = 15). The experimental group was submitted to running training (RT) and a strengthening protocol with NMES (1 kHz, modulated in 2 ms bursts, 50 Hz modulated burst frequency and 10% duty cycle, 15 min totaling 18 contractions per sessions) for 6 weeks, with 3 sessions per week, while controls were submitted to RT alone. The following variables were analyzed: peak isometric (ISO), concentric (CON), and eccentric (ECC) torque of the quadriceps muscle in voluntary contractions, ventilatory anaerobic thresholds (VATs), maximal oxygen uptake (VO2max), and oxygen cost of transport (OCT). RESULTS: The NMES group obtained higher values of ISO, 21.04% (p = 0.001), CON, 21.97% (p = 0.001) and ECC, 18.74% (p = 0.001) peak torque and VAT1, 9.56% (p = 0.001), as well as a statistically significant improvement in oxygen cost of transport at VAT1 when compared to controls (p = 0.001). CONCLUSION: NMES was effective in improving peak isometric, concentric and eccentric quadriceps muscle torque, in addition to being an interesting resource for enhancing sports performance in long-distance recreational runners and future clinical trials should be performed to compare the use of NMES to different forms of training over longer training periods.

Author Correction: Resistance training regulates gene expression of molecules associated with intramyocellular lipids, glucose signaling and fiber size in old rats.

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Resistance training regulates gene expression of molecules associated with intramyocellular lipids, glucose signaling and fiber size in old rats.

Sarcopenia is a complex multifactorial process, some of which involves fat infiltration. Intramyocellular lipid (IMCL) accumulation is postulated to play a role on sarcopenia during aging, which is believed to be due alterations in glucose homeostasis in the skeletal muscle. Sarcopenia, along with intramuscular lipids, is associated with physical inactivity. Resistance training (RT) has been indicated to minimize the age-induced muscle skeletal adaptations. Thus, we aimed to investigate the effects of RT on mRNA levels of regulatory components related to intramyocellular lipid, glucose metabolism and fiber size in soleus and gastrocnemius muscles of aged rats. Old male rats were submitted to RT (ladder climbing, progressive load, 3 times a week for 12 weeks). Age-induced accumulation of IMCL was attenuated by RT, which was linked to a PPARy-mediated mechanism, concomitant to enhanced regulatory components of glucose homeostasis (GLUT-4, G6PDH, Hk-2 and Gly-Syn-1). These responses were also linked to decreased catabolic (TNF-α, TWEAK/Fn14 axis; FOXO-1, Atrogin-1 and MuRF1; Myostatin) and increased anabolic intracellular pathways (IGF-1-mTOR-p70S6sk-1 axis; MyoD) in muscles of trained aged rats. Our results point out the importance of RT on modulation of gene expression of intracellular regulators related to age-induced morphological and metabolic adaptations in skeletal muscle.

Beneficial effects of resistance training on the protein profile of the calcaneal tendon during aging.

The calcaneal tendon (CT) is the most commonly injured tendon in the human body. Moreover, with advancing age, the amount of damage increases further. Resistance training (RT) could be used to minimize such damages. The aim of the present study was to obtain the identification, detailed protein cataloging and biochemical characterization based on the effects of the aging process and the RT in CT of rats. The analysis by liquid chromatography tandem-mass spectrometry showed 142 distinct proteins, however, only 29 proteins met the inclusion criteria and were analyzed. Aging causes a reduction in the abundance of seven proteins related to extracellular matrix organization, biological regulation and cellular processes. However, RT promoted the positive regulation of proteins important for the maintenance of healthy tendons: seven proteins in young trained and two in older trained group. This study contributes to a better understanding of molecular aspects of the tendon. The down regulation of proteins linked to mechanical function and extracellular matrix remodeling of the tendon during aging can contribute to the increase of injury and weakness in the tendon. Nevertheless, RT proved to be a tool to prevent these adverse effects during aging by increasing proteins involved in the functionality of the tendon.