Acupuncture is used for therapeutic purposes. The possible beneficial role of this therapy may be as an ergogenic resource for the performance of fitness variables in exercise and sports. To date, ...acupuncture has been associated with increases in muscle strength, aerobic power, and vertical jump performance, but the evidence is still inconclusive. This study aimed to verify the immediate effects of a single session of acupuncture on lower-limb muscle performance in 31 young, physically active women.
This randomized, controlled, double-blind pilot study was approved by the Research Ethics Committee and in the Brazilian Registry of Randomized Clinical Trials. After warming up on a treadmill, the participants underwent the vertical jump test, followed by an isometric strength test of the extensor muscles of both knees. Immediately after the tests, participants were randomly divided into the following groups: sham (SG), acupuncture (AG), and control (CG). After each intervention, all participants repeated the warm-up and functional tests.
There was a significant decrease in the mean and peak values of vertical jump height, in the sham and acupuncture groups, respectively. Furthermore, none of the groups showed changes in isometric muscle strength.
It was concluded that the proposed acupuncture protocol did not promote improve in lower-limb muscle performance parameters in young, physically active women.
Diabetes mellitus (DM) is associated with an increased risk of fractures, mainly due to impaired bone architecture and microvascular complications. Whether DM is also associated with increased risk ...of sarcopenia is not yet known, with studies yielding inconclusive results. The aim of this study was to systematically review and synthesize the best available evidence regarding the association between DM and sarcopenia risk. A comprehensive search was conducted in PubMed, CENTRAL and Scopus databases. Data are expressed as odds ratio (OR) with 95% confidence intervals (CI). The
I
2
index was employed for heterogeneity. Only studies which had implemented at least two of the three criteria for sarcopenia diagnosis (low muscle mass, muscle strength and/or muscle performance), as defined by the international studying groups, were included. Fifteen studies fulfilled eligibility criteria, yielding a total of 1832 patients with type 2 DM (T2DM) and 1159 cases of sarcopenia. Patients with T2DM demonstrated a higher risk of sarcopenia compared with euglycemic subjects (OR 1.55, 95% CI 1.25–1.91,
p
< 0.001;
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34.6%). This risk remained significant when analysis was restricted to studies matched for age and sex. Sarcopenia risk was independent of disease definition or study design. Notably, T2DM patients presented lower muscle performance and strength compared with euglycemic subjects, whereas no difference in muscle mass was observed between groups. Patients with T2DM have an increased risk of sarcopenia compared with euglycemic subjects.
Doping with anabolic-androgenic steroids (AAS) is common among both male and female athletes and is a growing public health problem. Review of historical data of systematic state-sponsored doping ...programs implemented by the German Democratic Republic in elite female athletes and from clinical trials of testosterone administration in non-athlete women suggests that AAS have ergogenic effects in women. The use of AAS in female athletes has been associated with adverse effects that include acne, hirsutism, deepening of the voice and menstrual disturbances; life-threatening adverse effects such as cardiac arrhythmias and sudden death have also been reported. Therefore, detection of AAS abuse in female athletes is important to ensure fairness in competition; at the same time, the athletes should be educated regarding the adverse consequences of AAS use. Although administration of exogenous androgens have been associated with ergogenic effects, it remains unclear whether endogenous hyperandrogenism seen in some medical conditions such as disorders of sexual development (DSD), congenital adrenal hyperplasia and polycystic ovary syndrome, confers any competitive advantage. Well-designed studies are needed to determine the effects of endogenous hyperandrogenism on athletic performance in female athletes.
Gromwell (Lithospermum erythrorhizon, LE) can mitigate obesity-induced skeletal muscle atrophy in C2C12 myotubes and high-fat diet (HFD)-induced obese mice. The purpose of this study was to ...investigate the anti-skeletal muscle atrophy effects of LE and the underlying molecular mechanism. C2C12 myotubes were pretreated with LE or shikonin, and active component of LE, for 24 h and then treated with 500 μM palmitic acid (PA) for an additional 24 h. Additionally, mice were fed a HFD for 8 weeks to induced obesity, and then fed either the same diet or a version containing 0.25% LE for 10 weeks. LE attenuated PA-induced myotubes atrophy in differentiated C2C12 myotubes. The supplementation of LE to obese mice significantly increased skeletal muscle weight, lean body mass, muscle strength, and exercise performance compared with those in the HFD group. LE supplementation not only suppressed obesity-induced skeletal muscle lipid accumulation, but also downregulated TNF-α and atrophic genes. LE increased protein synthesis in the skeletal muscle via the mTOR pathway. We observed LE induced increase of mitochondrial biogenesis and upregulation of oxidative phosphorylation related genes in the skeletal muscles. Furthermore, LE increased the expression of peroxisome proliferator-activated receptor-gamma coactivator-1 alpha and the phosphorylation of adenosine monophosphate-activated protein kinase. Collectively, LE may be useful in ameliorating the detrimental effects of obesity-induced skeletal muscle atrophy through the increase of protein synthesis and mitochondrial biogenesis of skeletal muscle.
Breast cancer fatigue (BCF) is a complex and multidimensional condition characterized by a persistent sense of physical and/or mental stiffness, resulting in a substantial impairment of ...health-related quality of life in breast cancer survivors. Aim of this prospective cohort study was to evaluate the feasibility and the effectiveness of a 4-week rehabilitation protocol on BCF, muscle mass, strength, physical performance, and quality of life in breast cancer (BC) survivors. We recruited adult BC women with a diagnosis of BCF, according to the International Classification of Diseases 10 criteria, referred to the Outpatient Service for Oncological Rehabilitation of a University Hospital. All participants performed a specific physical exercise rehabilitative protocol consisting of 60-min sessions repeated 2 times/week for 4 weeks. All outcomes were evaluated at the baseline (T0), at the end of the 4-week rehabilitation treatment (T1), and at 2 months follow up (T2). The primary outcome measure was the Brief Fatigue Inventory (BFI); secondary outcomes included: Fat-Free Mass and Fat Mass, assessed by Bioelectrical Impedance Analysis (BIA); Hand Grip Strength Test (HGS); Short Physical Performance Battery (SPPB); 10-meter walking test (10 MWT); 6-min walking test (6 MWT); European Organization for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ-C30). Thirty-six women (mean age: 55.17 ± 7.76 years) were enrolled in the study. Significant reduction of BCF was observed both after the 4-week rehabilitation treatment (T1) (BFI: 5.4 ± 1.6 vs. 4.2 ± 1.7; p = 0.004) and at the follow-up visit (T2) (BFI: 5.4 ± 1.6 vs. 4.4 ± 1.6; p = 0.004). Moreover, significant differences (p < 0.001) HGS, SPPB, 10 MWT, 6 MWT, and EORTC QLQ-C30 were found at T1, while at T2 all the outcome measures were significantly different (p < 0.05) from the baseline. The rehabilitation protocol seemed to be feasible, safe, and effective in reducing BCF, improving muscle mass and function, and improving HRQoL in a cohort of BC survivors. The results of this study could improve awareness of this underestimated disease, suggesting the definition of a specific therapeutic exercise protocol to reduce BCF.
Whole-body vibration (WBV) training has been employed alongside conventional exercise like resistance training to enhance skeletal muscle strength and performance. This systematic review examines the ...evidence regarding the effect of WBV on muscle activity, strength, and performance in healthy individuals. The Academic Search Ultimate, CINAHL, Cochrane CENTRAL, PubMed, ProQuest One Academic and SCOPUS databases were searched from 1990 to April 2023 to retrieve relevant studies. Methodological quality was assessed using the Modified Downs and Black checklist, while the level of evidence was evaluated through the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) tool. Even though the quality of the included studies was moderate to high, the level of evidence was very low owing to serious concerns with three or more GRADE domains (risk of bias, inconsistency, indirectness, imprecision, and publication bias) for each outcome of interest across studies. The review suggests that in WBV training, using moderate to high vibration frequencies (25–40 Hz) and high magnitudes (3–6 mm) can enhance muscle activation and strength in pelvis and lower limb muscles. However, findings regarding WBV effect on muscle performance measures were inconsistent. Future research with robust methodology is necessary in this area to validate and support these findings.
In skeletal muscle, interactions between contractile and connective tissue elements at multiple scales result in emergent properties that determine mechanical performance. One of these phenomena is ...architectural gearing, which is quantified as the ratio of muscle velocity to muscle fiber velocity. Many pennate muscles operate with a gear ratio greater than one because muscles shorten through a combination of muscle fiber shortening and fiber rotation. Within a muscle, gearing is variable across contractions. During low force contractions, muscles operate at high gear while muscles operate at low gear during high force contractions. This variable gearing has a significant impact on muscle performance as muscle architectural changes favor muscle speed during fast contractions and muscle force during slow, high force contractions. We hypothesize that gearing in any given contraction is determined by the dynamic interaction of fiber-generated forces, fluid force transmission, and the elastic behavior of intramuscular connective tissues. Because muscle is isovolumetric, muscle fibers must bulge radially when they shorten. Radial bulging and fiber-generated forces off-axis from the muscle line of action exert forces that load connective tissues that ensheath fibers, fascicles, and the whole muscle. The way in which fluid pressures and fiber forces interact to load connective tissues in three-dimensions remains poorly understood because of the complex and multiscale nature of these interactions. Here we review evidence for variable gearing in pennate muscles, present a conceptual model that describes the fundamental interactions that determine gearing, and discuss where gaps remain in our understanding of the determinants and consequences of muscle shape change and variable gearing.
An intermission in the training routine, in which older adults refrain from regular structured exercise, may have deleterious effects on muscle performance and bioelectric phase angle (PhA), which is ...a predictive marker for cellular integrity.
To determine the effects of a 2-week detraining period on PhA and muscular strength (MS) in trained older adults.
A total of 14 trained older adults (6 females) aged ≥65 years (77.2 ± 6.6) were assessed at baseline (i.e. trained condition) and after 2 weeks of detraining, where they refrained from their usual participation in structured exercise sessions. Whole-body resistance (R), reactance (Xc), and PhA were assessed using bioelectrical impedance analysis (BIA, single frequency, 50 kHz ± 1%, NutriLab, Akern). MS was assessed on both lower and upper limbs under isometric conditions. Differences between moments were examined using ANOVA for repeated measures, while adjusting for sex. Bioimpedance vector analysis (BIVA) was performed to evaluate changes in cellular function and body fluid content.
Detraining resulted in declines in PhA (−4.34%) (p = 0.017). There was a significant difference in the mean impedance vectors from baseline to post-detraining (p < 0.05), which were driven by decreases in reactance (Xc) relative to height (Xc/H) with little change in resistance (R) relative to height (R/H) for both males and females. No differences were found in MS for both the leg press (p = 0.992) and bench press (p = 0.166) tests.
A detraining period as short as 2-weeks is enough to cause alterations in the bodies bioelectrical properties, resulting in detrimental changes in PhA, due to alterations in cellular integrity, but not in MS. These results highlight the importance of maintaining structured exercise sessions in older adults, and reinforce the potential role of PhA as a sensitive predictor to detect acute changes in muscle cell integrity following alterations in exercise training.
•A detraining period as short as 2-weeks is enough to cause detrimental changes in PhA•PhA may be a sensitive marker to detect acute changes in muscle cell integrity following a period of detraining•Older adults should maintain a frequent practice of structured exercise activities in order to prevent adverse health changes
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