Sports Medicine and Health Science最新文献

Skeletal muscle anabolism is driven by numerous stimuli such as growth factors, nutrients (i.e., amino acids, glucose), and mechanical stress. These stimuli are integrated by the mechanistic target of rapamycin (mTOR) complex 1 (mTORC1) signal transduction cascade. In recent years, work from our laboratory and elsewhere has sought to unravel the molecular mechanisms underpinning the mTOR-related activation of muscle protein synthesis (MPS), as well as the spatial regulation of these mechanisms within the skeletal muscle cell. These studies have suggested that the skeletal muscle fiber periphery is a region of central importance in anabolism (i.e., growth/MPS). Indeed, the fiber periphery is replete with the substrates, molecular machinery, and translational apparatus necessary to facilitate MPS. This review provides a summary of the mechanisms underpinning the mTOR-associated activation of MPS from cell, rodent, and human studies. It also presents an overview of the spatial regulation of mTORC1 in response to anabolic stimuli and outlines the factors that distinguish the periphery of the cell as a highly notable region of skeletal muscle for the induction of MPS. Future research should seek to further explore the nutrient-induced activation of mTORC1 at the periphery of skeletal muscle fibers.

Black women have always been likened to being a less physically active group compared to women of other races/ethnicity, with reports of a high prevalence of obesity and other cardiometabolic diseases among them. The purpose of this study is to examine the health benefits of physical activity on women of color, as well as barriers that inhibit their participation.

We searched PubMed and Web of Science databases for relevant research articles. Included articles were: Published in the English Language from 2011 to February 2022; conducted predominantly on black women, African women, or African American women. Articles were identified, screened, and data extracted following the Preferred Reporting Item for Systematic Review and Meta-Analysis (PRISMA) guidelines.

The electronic search produced 2 043 articles, and 33 articles were reviewed after meeting the inclusion criteria. 13 articles focused on the benefits of physical activity while 20 articles addressed the barriers to physical activity. It was found that physical activity has various benefits for black women participants but they are being hindered from participation by some factors. These factors were grouped into four themes, namely Individual/Intrapersonal barriers, Socio-economic barriers, Social barriers, and Environmental barriers.

Various studies have examined the benefits and barriers of physical activity among women of different racial and ethnic backgrounds, but there have been very few studies of African women, with the majority focusing on one geographical area. In addition to exploring these benefits and barriers, this review offers recommendations on the areas researchers should focus on to promote physical activity in this population.

To determine whether existing exercise therapies can restore the joint position sense (JPS) deficits of patients with chronic ankle instability (CAI) when compared with controlled non-training patients. Seven databases were searched using ankle, injury, proprioception, and exercise-therapy-related terms. Peer-reviewed human studies in English that used the absolute errors score of joint position reproduction (JPR) test to compare the JPS of injured ankles in CAI patients before and after exercise therapy and non-training controls were included and analyzed. Demographic information, sample size, description of exercise therapies, methodological details of the JPR test, and absolute error scores were extracted by two researchers independently. Meta-analysis of the differences in JPS changes (i.e., absolute errors after treatment minus the baseline) between the exercise therapies and non-training controls was performed with the weighted mean difference (WMD) and 95% confidence interval (CI). Seven studies were finally included. Meta-analyses revealed significantly higher improvements in passive JPS during inversion with, WMD ​= ​−1.54° and eversion, of, WMD ​= ​−1.80°, after exercise therapies when compared with non-training controls. However, no significant changes in the impaired side active JPS were observed with regard to inversion and eversion. Existing exercise therapies may have a positive effect on passive JPS during inversion and eversion, but do not restore the active JPS deficits of injured ankles in patients with CAI when compared with non-training controls. Updated exercise components with a longer duration that focus on active JPS with longer duration are needed to supplement the existing content of exercise therapies.

Adiponectin has been demonstrated to be a mediator of insulin sensitivity; however, the underlined mechanisms remain unclear. SESN2 is a stress-inducible protein that phosphorylates AMPK in different tissues. In this study, we aimed to validate the amelioration of insulin resistance by globular adiponectin (gAd) and to reveal the role of SESN2 in the improvement of glucose metabolism by gAd. We used a high-fat diet-induced wild-type and SESN2^−/− C57BL/6J insulin resistance mice model to study the effects of six-week aerobic exercise or gAd administration on insulin resistance. In vitro study, C2C12 myotubes were used to determine the potential mechanism by overexpressing or inhibiting SESN2. Similar to exercise, six-week gAd administration decreased fasting glucose, triglyceride and insulin levels, reduced lipid deposition in skeletal muscle and reversed whole-body insulin resistance in mice fed on a high-fat diet. Moreover, gAd enhanced skeletal muscle glucose uptake by activating insulin signaling. However, these effects were diminished in SESN2^−/− mice. We found that gAd administration increased the expression of SESN2 and Liver kinase B1 (LKB1) and increased AMPK-T172 phosphorylation in skeletal muscle of wild-type mice, while in SESN2^−/− mice, LKB1 expression was also increased but the pAMPK-T172 was unchanged. At the cellular level, gAd increased cellular SESN2 and pAMPK-T172 expression. Immunoprecipitation experiment suggested that SESN2 promoted the formation of complexes of AMPK and LKB1 and hence phosphorylated AMPK. In conclusion, our results revealed that SESN2 played a critical role in gAd-induced AMPK phosphorylation, activation of insulin signaling and skeletal muscle insulin sensitization in mice with insulin resistance.

The effects of combined training (CT) on improving general health are well known, however, few studies have investigated the effects of low-volume CT. So, the aim of this study is to investigate the effects of 6 weeks of low-volume CT on body composition, handgrip strength (HGS), cardiorespiratory fitness (CRF) and affective response (AR) to exercise. Eighteen healthy, active young adult man (mean ​± ​SD, [20.06 ± 1.66] years; [22.23 ± 2.76] ​kg/m²) performed either a low-volume CT (EG, n ​= ​9), or maintained a normal life (CG, n ​= ​9). The CT was composed of three resistance exercises followed by a high intensity-interval training (HIIT) on cycle ergometer performed twice a week. The measures of the body composition, HGS, maximal oxygen consumption ($\dot{V}$O_2max) and AR to exercise were taken at baseline and after training for analysis. Furthermore, an ANOVA test of repeated measures and t-test paired samples were used with a p ​≤ ​0.05. The results showed that EG improved HGS (pre: [45.67 ± 11.84] ​kg vs. post: [52.44 ± 11.90] ​kg, p ​< ​0.01) and $\dot{V}$O_2max (pre: [41.36 ± 5.16] ​ml⋅kg^-1⋅min^-1 vs. post: [44.07 ± 5.98] ​ml⋅kg^-1⋅min^-1, p ​< ​0.01). Although, for all measures the body composition had not significant differences between weeks (p ​> ​0.05), nevertheless the feeling scale was positive in all weeks and without significant differences between them (p ​> ​0.05). Lastly, for active young adults, the low-volume CT improved HGS, CRF and had a positive outcome in AR, with less volume and time spent than traditional exercise recommendations.

Initially it was believed that phosphorylase was responsible for both glycogen breakdown and synthesis in the living cell. The discovery of glycogen synthase and McArdle's disease (lack of phosphorylase activity), together with the high P_i/glucose 1-P ratio in skeletal muscle, demonstrated that glycogen synthesis could not be attributed to reversal of the phosphorylase reaction. Rather, glycogen synthesis was attributable solely to the activity of glycogen synthase, subsequent to the transport of glucose into the cell. However, the well-established observation that phosphorylase was inactivated (i.e., dephosphorylated) during the initial recovery period after prior exercise, when the rate of glycogen accumulation is highest and independent of insulin, suggested that phosphorylase could play an active role in glycogen accumulation. But the quantitative contribution of phosphorylase inactivation was not established until recently, when studying isolated murine muscle preparations during recovery from repeated contractions at temperatures ranging from 25 to 35 °C. Thus, in both slow-twitch, oxidative and fast-twitch, glycolytic muscles, inactivation of phosphorylase accounted for 45%–75% of glycogen accumulation during the initial hours of recovery following repeated contractions. Such data indicate that phosphorylase inactivation may be the most important mechanism for glycogen accumulation under defined conditions. These results support the initial belief that phosphorylase plays a quantitative role in glycogen formation in the living cell. However, the mechanism is not via activation of phosphorylase, but rather via inactivation of the enzyme.

In a medical setting, such as the treatment of post-operative nosebleeds, nasal packing, including the use of nasal packs, nasal plugs or nasal tampons (NTs), is widely used to temporarily control anterior epistaxis. Although some literature has documented the use of NTs as a quick, easy and temporary solution to deal with anterior epistaxis in sports-induced nasal injuries, additional research is needed to appreciate on-field versus off-field efficacy, as well as the efficiency of different brands of NTs and packing materials.

This study examined the maximum joint angles and moments, and electromyography (EMG) activity of the lower limbs in an experienced Tai Chi (TC) practitioner in performing four dynamic (Repulse Monkey, Wave-hand in Clouds, Brush Knee Twist Step, and Lateral Forward Step) and three static TC movements (Starting Form, Hero Touch Sky, and Push Hand Back) and compared them with the measures from walking. Integrated EMG (iEMG) and peak EMG of the rectus femoris, adductor longus, tibialis anterior, semitendinosus, erector spinae, gluteus medius, tensor fasciae latae, medial and lateral gastrocnemius muscles were analyzed. One-way analysis of variance showed that compared with walking, TC presented 1) significantly larger hip flexion (71.4° vs. 42.2°) and abduction angles (11.9° vs. 5.3°), smaller knee flexion (45.2° vs. 71.1°) and abduction angles (13.0° vs. 27.7°), larger ankle dorsiflexion (41.4° vs. 11.3°) and abduction angles (8.8° vs. 7.2°); 2) hip flexion moment and knee flexion and abduction moment were significantly larger. Ankle dorsiflexion moment were significantly smaller, whereas ankle abduction moment was significantly larger in two TC movements; and 3) the EMG activity of the muscles in TC varied from 10% to 610% of walking. The knee extensors, hip adductors and abductors had significantly higher peak EMG (430% ​± ​40%, 240% ​± ​30%, and 320% ​± ​90%) and iEMG values (610% ​± ​30%, 311% ​± ​30%, and 1.4% ​± ​20%), respectively. The findings suggested that these TC movements could be a good option for the improvement of muscle strength and range of motion of the lower limbs.

A one metabolic-equivalent-of-task increase in peak aerobic fitness (peak MET) is associated with a clinically relevant improvement in survival risk and all-cause mortality. The co-dependent impact of free-living physical behaviours on aerobic fitness are poorly understood. The purpose of this study was to investigate the impact of theoretically re-allocating time spent in physical behaviours on aerobic fitness. We hypothesized that substituting sedentary time with any physical activity (at any intensity) would be associated with a predicted improvement in aerobic fitness. Peak volume rate of oxygen uptake ($\dot{V}$O₂peak) was assessed via indirect calorimetry during a progressive, maximal cycle ergometer protocol in 103 adults (52 females; [38 ± 21] years; [25.0 ± 3.8] kg/m²; $\dot{V}$O₂peak: [35.4 ± 11.5] ml·kg⁻¹·min⁻¹). Habitual sedentary time, standing time, light- (LPA), moderate- (MPA), and vigorous-physical activity (VPA) were assessed 24-h/day via thigh-worn inclinometry for up to one week (average: [6.3 ± 0.9] days). Isotemporal substitution modelling examined the impact of replacing one physical behaviour with another. Sedentary time (β = −0.8, 95% CI: [-1.3, −0.2]) and standing time (β = −0.9, 95%CI: [−1.6, −0.2]) were negatively associated with $\dot{V}$O₂peak, whereas VPA was positively associated with relative $\dot{V}$O₂peak (β = 9.2, 95%CI: [0.9, 17.6]). Substituting 30-min/day of VPA with any other behaviour was associated with a 2.4–3.4 higher peak MET. Higher standing time was associated with a lower aerobic fitness. As little as 10-min/day of VPA predicted a clinically relevant 0.8–1.1 peak MET increase. Theoretically, replacing any time with relatively small amounts of VPA is associated with improvements in aerobic fitness.

Knee Osteoarthritis (KOA) is the most common type of knee joint injury and also a risk factor for multiple health consequences and is prevalent among older women. The updated clinical guidelines for KOA treatment by the American Rheumatism Association recommend Tai Chi exercise. However, a literature review outlined limitations in Tai Chi intervention implementations. This study aimed to address some of the gaps. This study selected thirty female patients to participate in Tai Chi exercises and undergo relevant tests. The subjects were randomly assigned to Tai Chi or education groups. Independent sample t-tests were conducted to compare the difference in health indicators between the two groups after the intervention. The difference-in-differences (DID) regression was performed to assess the difference in the health outcomes between the two groups at baseline and follow-up and the difference in the differences. After the completion of the intervention, the Tai Chi group reported significantly improved KOA symptoms, physical fitness, and health status indicators than the control group. Specifically, the group differences were significantly larger at the baseline than at the follow-up. Our findings provide compelling evidence of the effects of the innovative Tai Chi exercise prescription specifically designed for KOA patients. The empirical evidence on its effectiveness in alleviating KOA symptoms and improving the overall health of middle-aged and elderly women with KOA suggested that Tai Chi intervention exercise has huge prospects for integration in KOA rehabilitation therapy.