Journal of Sport and Health Science最新文献

Background: Ischemic preconditioning (IPC) is purported to have beneficial effects on athletic performance, although findings are inconsistent, with some studies reporting placebo effects. The majority of studies have investigated IPC alongside a placebo condition, but without a control condition that was devoid of experimental manipulation, thereby limiting accurate determination of the IPC effects. Therefore, the aims of this study wereto assess the impact of the IPC intervention, compared to both placebo and no intervention, on exercise capacity and athletic performance.

Methods: A systematic search of PubMed, Embase, SPORTDiscus, Cochrane Library, and Latin American and Caribbean Health Sciences Literature (LILACS) covering records from their inception until July 2023 was conducted. To qualify for inclusion, studies had to apply IPC as an acute intervention, comparing it with placebo and/or control conditions. Outcomes of interest were performance (force, number of repetitions, power, time to exhaustion, and time trial performance), physiological measurements (maximum oxygen consumption, and heart rate), or perceptual measurements (RPE). For each outcome measure, we conducted 3 independent meta-analyses (IPC vs. placebo, IPC vs. control, placebo vs. control) using an inverse-variance random-effects model. The between-treatment effects were quantified by the standardized mean difference (SMD), accompanied by their respective 95% confidence intervals. Additionally, we employed the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach to assess the level of certainty in the evidence.

Results: Seventy-nine studies were included in the quantitative analysis. Overall, IPC demonstrates a comparable effect to the placebo condition (using a low-pressure tourniquet), irrespective of the subjects'training level (all outcomes presenting p > 0.05), except for the outcome of time to exhaustion, which exhibits a small magnitude effect (SMD = 0.37; p = 0.002). Additionally, the placebo exhibited effects notably greater than the control condition (outcome: number of repetitions; SMD=0.45; p = 0.03), suggesting a potential influence of participants' cognitive perception on the outcomes. However, the evidence is of moderate to low certainty, regardless of the comparison or outcome.

Conclusion: IPC has significant effects compared to the control intervention, but it did not surpass the placebo condition. Its administration might be influenced by the cognitive perception of the receiving subject, and the efficacy of IPC as an ergogenic strategy for enhancing exercise capacity and athletic performance remains questionable.

Background: Iron facilitates key biological functions underpinning sports performance, and up to 60% of female athletes experience iron deficiency. However, the effects of iron deficiency on sports performance in female athletes is unclear, as are the degree of benefits of iron supplementation (FeSup). This study characterizes the effects of iron deficiency and FeSup on sports performance in high-level female athletes.

Methods: Searches of the electronic databases Medline, SPORTDiscus, Web of Science, Scopus, and CINAHL were performed in July 2023. Studies were included that evaluated the effects of iron deficiency or FeSup on sports performance in high-level (maximal oxygen uptake (VO_2max) > 45 mL/kg/min, or trained > 5 h/week) iron deficient (ID) (serum ferritin (sFer) < 40 µg/L) female athletes. Studies were assessed using a modified Downs and Black Quality Assessment Checklist.

Results: A total of 23 studies comprising 669 athletes (age range: 13-47 years) across 16 sports were included in the review. Iron deficiency negatively affects endurance performance by 3%-4%. However, endurance performance improved by 2%-20% when ID athletes were treated with 100 mg/day of elemental iron for up to 56 days via oral supplementation, or bi-daily via parenteral administration over 8-10 days. ID non-anemic athletes with low sFer stores may be predisposed to reduced maximal aerobic capacity. However, maximal aerobic capacity improved by 6%-15% following 16-100 mg/day of elemental iron for 36-126 days. Isokinetic strength and anaerobic power performance may be impeded (-23% to +4%) among ID athletes, but the effect of FeSup on anaerobic power varied markedly (-5% to +9%) following 100 mg/day of elemental iron over 42-56 days, or 100 mg of elemental iron bi-daily over 8-10 days. The quality of studies was moderate (77%), ranging from low (57%) to high (100%). Moststudies (n = 18) contained group sizes ≤ 20 athletes, thus limiting the likelihood of detecting significant effects (statistical power > 0.80).

Conclusion: High-level ID female athletes experience a negative impact on endurance performance, which can be improved by supplementing with ∼100 mg of elemental iron per day or bi-daily. The decrements in other performance parameters characterizing a range of sports coincide with the severity of iron deficiency.

Objective: To provide comparative evidence on the effectiveness of various lifestyle interventions on body composition management for preschool and school-aged children.

Methods: PubMed (Medline), Embase, CINAHL, and Web of Science were systematically searched for this network meta-analysis. Randomized controlled studies (RCTs) that included children aged 4-12 years with no physical or mental conditions; performed at least 1 type of lifestyle intervention; reported change in body mass index (BMI), BMI z-score, or body fat percentage (BFP); and were published between January 2010 and August 2023 were included.

Results: The final analysis included 91 RCTs with aggregate data for 58,649 children. All interventions were categorized into single-arm approaches (physical activity, diet, behavioral and informational support) and combined arms approaches (bicomponent and multicomponent treatment). Multicomponent treatment showed significant effectiveness on the reduction of BMI (mean deviation (MD) = 0.49, 95% confidence interval (95%CI): -0.88 to -0.12), BMI z-score (MD = -0.11, 95%CI: -0.18 to -0.04), and BFP (MD = -1.69, 95%CI: -2.97 to -0.42) compared to the usual care condition. Bicomponent treatment also significantly reduced BMI (MD = -0.28, 95%CI: -0.54 to -0.04) and BMI z-score (MD = -0.07, 95%CI: -0.12 to -0.02) compared to usual care.

Conclusion: Interventions targeting multiple lifestyle components achieved greater reductions in children's BMI and BFP. Among single-component approaches, physical activity engagement emerged as the most effective. These findings should guide practitioners in recommending comprehensive lifestyle modifications for children. Moreover, children with higher initial BMI and body fat levels tend to exhibit more positive responses to lifestyle interventions aimed at managing obesity.

Background: Statins are the cornerstone of low-density lipoprotein cholesterol (LDL-C)-lowering therapy; however, the therapeutic efficacy of statins in countering atherosclerotic cardiovascular disease (ASCVD) is compromised by the concurrent elevation of proprotein convertase subtilisin/kexin type 9 (PCSK9), a pivotal molecule that increases LDL-C levels. Aerobic exercise lowers PCSK9 levels, but the underlying mechanism remains unclear. Therefore, we investigated how aerobic exercise can ameliorate statin-induced increases in PCSK9 levels.

Methods: Three-week-old male American Institute of Cancer Research (ICR) mice were fed a high-fat-cholesterol diet (HFD) for 12 weeks and then administered atorvastatin alone or atorvastatin combined with aerobic exercise (Statin+Ex). Moreover, a total of 165 participants with stable coronary heart disease (CHD) enrolled at the inpatient and outpatient departments of the Second Xiangya Hospital of Central South University from January 2018 to July 2020 were randomized into the Statin group (male/female = 51/33) and Statin+Ex group (male/female = 52/29). Patients in the Statin+Ex group underwent treadmill exercise of 45-60 min/day for 7 days.

Results: Aerobic exercise effectively alleviated statin-induced PCSK9 upregulation in human patients with CHD and hypercholesterolemic ICR mice (all p < 0.05). Mechanistically, our findings revealed that aerobic exercise induced elevated epoxyeicosatrienoic acids (EETs) plasma levels while concurrently reducing the activity of soluble epoxide hydrolase (sEH) (all p < 0.05), an enzyme responsible for EETs degradation. Further, EETs significantly suppressed PCSK9 expression, subsequently reducing the LDL-C levels (all p < 0.05); this effect was mediated via the activation of the Forkhead box O3a-Silent mating type information regulation 2 homolog 6 (FoxO3a-Sirt6) axis, with no impact on the Sterol Regulatory Element Binding Protein 2 and 3-hydroxy-3-methylglutaryl-CoA reductase (SREBP2-HMGCR) pathway.

Conclusion: Our study sheds light on the paradigm of "Exercise is Medicine", providing evidence to support the use of statins combined with exercise in reducing LDL-C levels, and unveils potential avenues for clinical applications of sEH inhibitors, presenting novel prospects for therapeutic interventions in ASCVD.

The discovery that contracting skeletal muscle generates reactive oxygen species (ROS) was first reported over 40 years ago. The prevailing view in the 1980s was that exercise-induced ROS production promotes oxidation of proteins and lipids resulting in muscle damage. However, a paradigm shift occurred in the 1990s as growing research revealed that ROS are signaling molecules, capable of activating transcriptional activators/coactivators and promoting exercise-induced muscle adaptation. Growing evidence supports the notion that reduction-oxidation (redox) signaling pathways play an important role in the muscle remodeling that occurs in response to endurance exercise training. This review examines the specific role that redox signaling plays in this endurance exercise-induced skeletal muscle adaptation. We begin with a discussion of the primary sites of ROS production in contracting muscle fibers followed by a summary of the antioxidant enzymes involved in the regulation of ROS levels in the cell. We then discuss which redox-sensitive signaling pathways promote endurance exercise-induced muscle adaptation and debate the strength of the evidence supporting the notion that redox signaling plays an essential role in muscle adaptation to endurance exercise training. In hopes of stimulating future research, we highlight several important unanswered questions in this field.

Background: Newly diagnosed breast cancer patients experience symptoms that may affect their quality of life, treatment outcomes, and survival. Preventing and managing breast cancer-related symptoms soon after diagnosis is essential. The purpose of this study was to investigate the associations between health-related fitness (HRF) and patient-reported symptoms in newly diagnosed breast cancer patients.

Methods: This study utilized baseline data from the Alberta Moving Beyond Breast Cancer Cohort Study that were collected within 90 days of diagnosis. HRF measures included peak cardiopulmonary fitness (peak volume of oxygen consumption (VO_2peak)), maximal muscular strength and endurance, flexibility, and body composition. Symptom measures included depression, sleep quality, and fatigue. Adjusted multivariable logistic regression was performed for analyses.

Results: Of 1458 participants, 51.5% reported poor sleep quality, 26.5% reported significant fatigue, and 10.4% reported moderate depression. In multivariable-adjusted models, lower relative VO_2peak was independently associated with a greater likelihood of all symptom measures, including moderate depression (p < 0.001), poor sleep quality (p = 0.009), significant fatigue (p = 0.008), any symptom (p < 0.001), and multiple symptoms (p < 0.001). VO_2peak demonstrated threshold associations with all symptom measures such that all 3 lower quartiles exhibited similar elevated risk compared to the highest quartile. The strength of the threshold associations varied by the symptom measure with odds ratios ranging from ∼1.5 for poor sleep quality to ∼3.0 for moderate depression and multiple symptoms. Moreover, lower relative upper body muscular endurance was also independently associated with fatigue in a dose-response manner (p = 0.001), and higher body weight was independently associated with poor sleep quality in an inverted U pattern (p = 0.021).

Conclusion: Relative VO_2peak appears to be a critical HRF component associated with multiple patient-reported symptoms in newly diagnosed breast cancer patients. Other HRF parameters may also be important for specific symptoms. Exercise interventions targeting different HRF components may help newly diagnosed breast cancer patients manage specific symptoms and improve outcomes.

Background: A quality diet and an active lifestyle are both important cornerstones of cardiovascular disease (CVD) prevention. However, despite their interlinked effects on metabolic health, the 2 behaviors are rarely considered jointly, particularly within the context of CVD prevention. We examined the independent, interactive, and joint associations of diet and physical activity with CVD hospitalization, CVD mortality, and all-cause mortality.

Methods: CVD-free Australian participants aged 45-74 years (n = 85,545) reported physical activity, diet, sociodemographic, and lifestyle characteristics at baseline (2006-2009) and follow-up (2012-2015), and data were linked to hospitalization and death registries (03/31/2019 for CVD hospitalization and all-cause mortality and 12/08/2017 for CVD mortality). Diet quality was categorized as low, medium, and high based on meeting dietary recommendations. Physical activity was operationalized as (a) total moderate-to-vigorous physical activity (MVPA) as per guidelines, and (b) the composition of MVPA as the ratio of vigorous-intensity physical activity (VPA) to total MVPA. We used a left-truncated cause-specific Cox proportional hazards model using time-varying covariates.

Results: During a median of 10.7 years of follow-up, 6576 participants were admitted to the hospital for CVD and 6581 died from all causes (876 from CVD during 9.3 years). A high-quality diet was associated with a 17% lower risk of all-cause mortality than a low-quality diet, and the highest MVPA category (compared with the lowest) was associated with a 44% and 48% lower risk of CVD and all-cause mortality, respectively. Multiplicative interactions between diet and physical activity were non-significant. For all outcomes, the lowest risk combinations involved a high-quality diet and the highest MVPA categories. Accounting for total MVPA, some VPA was associated with further risk reduction of CVD hospitalization and all-cause mortality.

Conclusion: For CVD prevention and longevity, one should adhere to both a healthy diet and an active lifestyle and incorporate some VPA when possible.