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Muscles, Volume 1, Issue 3 (December 2022) – 4 articles

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10 pages, 1634 KiB  
Communication
Characterizing the Effects of Voluntary Wheel Running on Cardiac SERCA Function in Ovariectomized Mice
by Bianca M. Marcella, Mia S. Geromella, Ahmad Mohammad, Jacob Sweezey-Munroe, Rebecca E. K. MacPherson and Val A. Fajardo
Muscles 2022, 1(3), 152-161; https://doi.org/10.3390/muscles1030016 - 10 Dec 2022
Viewed by 1318
Abstract
The sarco(endo)plasmic reticulum Ca2+ ATPase (SERCA) actively transports Ca2+ into the sarcoplasmic reticulum to facilitate cardiac muscle relaxation. Phospholamban (PLN) allosterically inhibits SERCA, and an imbalance of SERCA2a, dominant cardiac isoform, and PLN content disrupts Ca2+ homeostasis and cardiac contractility. [...] Read more.
The sarco(endo)plasmic reticulum Ca2+ ATPase (SERCA) actively transports Ca2+ into the sarcoplasmic reticulum to facilitate cardiac muscle relaxation. Phospholamban (PLN) allosterically inhibits SERCA, and an imbalance of SERCA2a, dominant cardiac isoform, and PLN content disrupts Ca2+ homeostasis and cardiac contractility. A previous study has shown that ovariectomized (OVX) rats have reduced SERCA activity due to lowered SERCA2a and increased PLN content. Furthermore, it was found that forced treadmill running in OVX rats restored SERCA activity and protein content levels. Here, we investigated whether voluntary wheel running (VWR) would produce similar effects on cardiac SERCA function in OVX mice. Female mice were divided into the following groups for 8 weeks: SHAM; OVX; SHAM + VWR; and OVX + VWR (n = 10/group). SERCA activity and Ca2+ uptake assays were performed in cardiac muscle homogenates. Protein levels of SERCA2, PLN, and pPLN were determined via Western blot analysis. We found statistical interactions for Ca2+ uptake, maximal SERCA activity, and SERCA2a content where VWR increased these parameters in SHAM mice but not in OVX mice. We detected a main effect of OVX on PLN content, and main effects of OVX and VWR on pPLN content. The OVX mice ran significantly less than the SHAM mice, suggesting that estrogen deprivation and lack of regular exercise may blunt the effects of voluntary aerobic exercise on cardiac SERCA function. Full article
(This article belongs to the Special Issue Feature Papers in Muscles)
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9 pages, 273 KiB  
Article
Reduction in Skeletal Muscle Mass in Progressive Supranuclear Palsy in Comparison with Parkinson’s Disease: A Preliminary Retrospective Longitudinal Study
by Yasuyuki Takamatsu and Ikuko Aiba
Muscles 2022, 1(3), 143-151; https://doi.org/10.3390/muscles1030015 - 19 Nov 2022
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Abstract
Progressive supranuclear palsy (PSP) manifests with the loss of skeletal muscle mass, but the longitudinal changes have not been investigated. We studied changes in body composition, including in skeletal muscle mass, in patients with PSP twice, approximately 1 year or more apart, and [...] Read more.
Progressive supranuclear palsy (PSP) manifests with the loss of skeletal muscle mass, but the longitudinal changes have not been investigated. We studied changes in body composition, including in skeletal muscle mass, in patients with PSP twice, approximately 1 year or more apart, and we compared these measurements with those of patients with Parkinson’s disease (PD). The total number of participants was 42: 10 men had PD, 13 men had PSP, 8 women had PD, and 11 women had PSP. Using a body composition analyzer, we measured such parameters as body mass index (BMI), skeletal muscle mass, basal metabolic rate (BMR), body fat percentage (BFP), and the ratio of extracellular water to total body water. We also calculated the skeletal muscle mass index (SMI). We measured the Barthel index to assess activities of daily living. The Barthel index was lower in patients with PSP than in those with PD at the first evaluation, and it worsened by the time of the second evaluation. In men with PSP, skeletal muscle mass was far more reduced than in those with PD, but no such changes were found among women with either disease. The SMI of men with PSP was correlated significantly with BMI, BMR, BFP, and the Barthel index. Skeletal muscle mass diminished faster in patients with PSP, especially in men, than in patients with PD, probably because of inactivity. Full article
(This article belongs to the Special Issue Feature Papers in Muscles)
10 pages, 1402 KiB  
Article
Effects of Blood Flow Restricted Exercise on Electromechanical Delay and Time to Peak Force after Task Failure: A Randomized Crossover Trial
by Mikhail Santos Cerqueira, Maria Lira, Raiff Simplicio da Silva, Marco Machado and Rafael Pereira
Muscles 2022, 1(3), 133-142; https://doi.org/10.3390/muscles1030014 - 4 Nov 2022
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Abstract
Introduction: Electromechanical delay (ED) and time to peak force (TPF) could be used to investigate the central or peripheral sources of performance decline in fatiguing tasks. Exercise with partial blood flow restriction (BFR) has been shown to induce fatigue, but the repercussions of [...] Read more.
Introduction: Electromechanical delay (ED) and time to peak force (TPF) could be used to investigate the central or peripheral sources of performance decline in fatiguing tasks. Exercise with partial blood flow restriction (BFR) has been shown to induce fatigue, but the repercussions of exercise with partial BFR on ED and TPF are unclear. The present study aimed to compare the ED and TPF after an intermittent isometric task until failure with BFR and free blood flow (FBF). Methods: In this crossover randomized clinical trial, 15 healthy and physically active men volunteered in this study. Volunteers performed two intermittent isometric handgrip exercise (IIHE) to failure (72 h apart), combined with either BFR or FBF. Maximum voluntary isometric force (MVIF) concomitant with the electromyographic activity of the wrist and finger flexor muscles were assessed before (PRE) and one minute after (POST) the task failure. Within (PRE vs. POST) and between comparisons (eFBF vs. eBFR) of peak force, time to peak force, rate of force development (RFDpeak) and ED were carried out. Results: No significant between-intervention differences were identified pre- or post-exercise. Peak force and RFDpeak reduced significantly after both blood flow conditions (p < 0.05), but without between-condition difference. TPF was statistically higher after exercise only in the FBF intervention (p < 0.05). None of the interventions induced a significant change in the ED after IIHE. Conclusion: ED and TPF were similar after BFR and FBF, indicating both conditions induce similar acute performance impairments after IIHE, which seems not to be caused by local (i.e., muscular) factors, but probably by central (i.e., neural) factors. Full article
(This article belongs to the Special Issue Feature Papers in Muscles)
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12 pages, 829 KiB  
Article
Creatine Supplementation Improves Muscular Performance without Additional Impact on the Cardiovascular System in Trained Women
by Katia S. Azevedo, Steven B. Machek, Abby E. Lewis, Warleyson J. S. Azevedo, Jeffrey M. Willardson, Rafael Pereira and Marco Machado
Muscles 2022, 1(3), 121-132; https://doi.org/10.3390/muscles1030013 - 26 Oct 2022
Viewed by 3090
Abstract
Creatine monohydrate supplementation in females is largely under-represented in the literature, and their potentially differential hemodynamic responses are unknown. Methods: Twenty-eight resistance-trained women (25.5 ± 6.1 years, 59.7 ± 6.3 kg, 163 ± 5 cm) were randomly assigned to the supplement creatine monohydrate [...] Read more.
Creatine monohydrate supplementation in females is largely under-represented in the literature, and their potentially differential hemodynamic responses are unknown. Methods: Twenty-eight resistance-trained women (25.5 ± 6.1 years, 59.7 ± 6.3 kg, 163 ± 5 cm) were randomly assigned to the supplement creatine monohydrate (CRE; 5 g creatine monohydrate + 5 g dextrose) or placebo (PLA; 10 g dextrose) four times per day for 7 days in a double-blind fashion. Each subject subsequently completed resistance training sessions (3 × week) for four weeks with four sets to muscular failure of both half-squat and leg press exercises. The change in body mass (BM), exercise repetition number (REP), rated perceived exertion (RPE), and cardiovascular variables were assessed (sessions 1, 6, and 12). Statistical analyses were performed at a significance level of p ≤ 0.05. Results: Analyses revealed a significant CRE-specific BM increase (p = 0.013), as well as significantly greater half-squat (p = 0.006) and leg press (p = 0.017) REP per set versus PLA. Additionally, CRE demonstrated significantly lower relative RPE values at session 12 compared with previous sessions. Any significant main or interaction effects were observed for the studied cardiovascular variable. Conclusions: The present data substantiate the creatine’s efficacy to improve muscular performance in females while demonstrating the safety of combined creatine monohydrate supplementation and resistance training on cardiovascular parameters. Full article
(This article belongs to the Special Issue Feature Papers in Muscles)
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