Medicine and Science in Sports and Exercise最新文献

Purpose: To examine the incidence of injuries among different menstrual phases in eumenorrheic cycles and abnormal menstrual cycles in female athletes.

Methods: This prospective cohort study recruited female athletes involved in collegiate, semi-professional, or professional team sports. Participating athletes self-reported their menstruation during the follow-up period. Menstrual cycles were classified as polymenorrhea, oligomenorrhea/amenorrhea, and eumenorrhea. Eumenorrheic cycles were further divided into estimated follicular phase (EFP), estimated ovulatory phase (EOP), and estimated luteal phase (ELP). Time-loss injuries and sports participation status were recorded by team medical staff. Incidence rates for each cycle and phase category were calculated per 1,000 athlete-days with 95% confidence intervals (CI). Incidence rate ratios (IRR) were utilized to compare risks among cycle and phase categories.

Results: Data from 316 female athletes were analyzed over a median follow-up period of 337 days. The incidence rates during eumenorrheic, oligomenorrheic/ amenorrheic, and polymenorrheic cycles were 3.10 (95% CI, 2.61-3.67), 2.11 (95% CI, 1.44-2.98), and 4.84 (95% CI, 2.77-7.86) per 1,000 athlete-days, respectively. Among eumenorrheic phases, the highest incidence rate was in the EOP at 5.14 (95% CI, 3.26-7.7), followed by the EFP at 3.19 (95% CI, 2.47-4.04) and the ELP at 2.52 (95% CI, 1.85-3.35). The incidence rate ratios (IRRs) for EOP compared to EFP and ELP were 1.61 (95% CI, 1.004-2.586) and 2.04 (95% CI, 1.238-3.357), respectively.

Conclusions: Injury risk is significantly higher during the EOP compared to the EFP and ELP in eumenorrheic cycles. Injury incidence was found to be lower during oligomenorrheic/amenorrheic cycles than during eumenorrheic cycles. Future studies should explore the factors contributing to the heightened injury risk during the EOP and the observed reduction in injury rates during oligomenorrheic/amenorrheic cycles.

Introduction: The relationship between cognitive tasks and physical performance has garnered significant attention, with evidence suggesting that cognitive effort before exercise may impair physical performance. However, recent findings challenge the robustness of this effect, necessitating a reassessment of the mechanisms linking cognitive load to physical performance. This study introduces a novel approach to address methodological limitations, emphasizing individualized cognitive task difficulty and duration. Using techniques such as Temporal Experience Tracing (TET) and psychophysiological monitoring, we explore the dynamics between cognitive effort, subjective states, and physical performance.

Methods: In a pre-registered, randomized, within-participant design experiment, 21 recreational athletes completed a running time to exhaustion test at 90% of their maximal aerobic speed after performing a cognitive task until failure or watching a self-selected documentary. Pupillometry and six subjective dimensions were measured with the TET during task performance.

Results: We found that 1) subjective changes during effortful tasks are not limited to a single experience, such as mental fatigue or boredom, but can be grouped into distinct patterns; 2) the individualized and demanding cognitive task, completed before exercise did not impair subsequent physical performance; 3) pupil size reliably reflected cognitive load and is partially related to changes in subjective states, while fixation on the stimulus decreased over time, especially during high-demand periods.

Conclusions: These results do not support the effect of performing a highly demanding cognitive task on subsequent strenuous physical performance. Instead, they reveal the richness of the subjective experience linked to cognitive performance that goes beyond mere mental fatigue. Overall, we show a novel way to understand the interplay between cognitive and physical performance.

Purpose: This study aimed to investigate the relationship of physical activity levels on white matter volume in post-9/11 Veterans.

Methods: The study consisted of post-9/11 Veterans enrolled in the Translational Research Center for TBI and Stress Disorders (TRACTS) longitudinal study at VA Boston Healthcare System. Participants were retrospectively categorized into two groups: a Vigorous group of Veterans who participated in vigorous-intensity physical activity (n = 84), and a No Vigorous group of Veterans who reported no participation of vigorous-intensity physical activity (n = 62). Physical activity was measured using the International Physical Activity Questionnaire (IPAQ), and Veterans underwent quantitative brain magnetic resonance imaging (MRI) to obtain regional white matter volumes.

Results: A cross-sectional analysis revealed trends of greater white matter volume throughout brain regions associated with cognitive functions and emotional regulation in the Vigorous group compared to the No Vigorous group. Following correction for multiple comparison, significant differences between groups were found in the right [p-corrected = 0.049] and left [ p-corrected = 0.049] precuneus. Furthermore, an interaction analysis showed that the difference in white matter volume between vigorous and non-vigorous activity groups was more pronounced in individuals with PTSD compared to those without PTSD.

Conclusions: These data offer new insights suggesting vigorous physical activity is associated with neural benefits in Veterans with PTSD.

Purpose: This study investigates the intra- and inter-individual time courses of physiological adaptation to high-intensity interval training (HIIT), comparing single and duplicate pre-to-post testing with session-by-session analysis to more accurately identify "genuine" adaptations.

Methods: Seventeen participants (nine men) engaged in repeated 4x4 min HIIT sessions (2 times/week) until a meaningful change in the primary outcome i.e. relative peak oxygen uptake (VO2peak) was observed.

Results: Mixed-effects model analysis revealed a significant improvement for VO2peak for both session-by-session (estimate: 0.18, p < 0.01, d = 0.11) analysis and duplicate pre-to-post analysis (estimate: 3.97, p < 0.01, ηp2 = 0.36). Session-by-session analysis revealed significant variability in physiological responses, with a low coefficient of variation (CV) for VO2peak (3.49% + 1.96) and estimated maximum stroke volume (SVmax) (3.07% ± 1.92) and, indicating their reliability for detecting small changes. With a CV of 22.14% ± 13.80 submaximal blood lactate ([BLa]submax) was the least reliable parameter. With session-by-session analysis VO2peak was the only parameter displaying 100% positive responders after 9.5 ± 3.8 sessions. Additionally, session-by-session analysis revealed lower proportions of participants with positive adaptations for submaximal VO2 and SVmax, but higher proportions for submaximal respiratory exchange ratio and rating of perceived exertion compared with pre-to-post analysis.

Conclusions: This study highlights the value of longitudinal assessments for understanding the variability and dynamics of training adaptations. By addressing the limitations of pre-to-post evaluations, the findings emphasize the importance of frequent monitoring to accurately capture individual responses, thereby advancing strategies for optimizing exercise interventions across diverse populations.

Purpose: This study evaluated whether recombinant human erythropoietin (rhEpo) treatment combined with hypoxia provided an additive effect on hemoglobin mass (Hbmass) and V̇O2peak compared to altitude or rhEpo alone.

Methods: 39 participants underwent two interventions, each containing 4 weeks baseline (PRE 1-4), 4 weeks exposure at sea level or 2,320 m of altitude (INT 1-4), and 4 weeks follow-up (POST 1-4). Participants were randomly assigned to 20 IU·kg-1 rhEpo or placebo injections every second day for 3 weeks during the exposure period at sea level (SL-EPO n = 25, SL-PLA n = 9) or at altitude (ALT-EPO n = 12, ALT-PLA n = 27).

Results: Hbmass displayed a significant time×treatment effect (P < 0.001) when comparing ALT-EPO and ALT-PLA. Specifically, the increase in Hbmass was higher (P < 0.05 to P < 0.001) for ALT-EPO from INT 2 to POST 3 except for POST 2. Similarly, a significant time×treatment effect (P < 0.001) existed for changes in Hbmass when comparing ALT-EPO with SL-EPO, with the increase in Hbmass being higher (P < 0.01 to P < 0.001) for ALT-EPO from INT 2 to POST 4. A significant time×treatment effect was present when SL-PLA was compared with ALT-PLA (P < 0.05) and SL-EPO (P < 0.05). For V̇O2peak the time×treatment interaction was not significant when comparing ALT-EPO to ALT-PLA. However, when ALT-EPO was compared with SL-EPO, a significant time×treatment interaction existed (P < 0.001) due to a decrease in V̇O2peak during altitude.

Conclusions: The combined treatment of micro-doses of rhEpo and altitude exposure results in an additive increase in Hbmass but does not significantly enhance V̇O2peak compared to each treatment alone.

Purpose: Substrate metabolism during exercise may vary across the menstrual cycle (MC) phases, likely due to estradiol (E2) and progesterone (P4). This study examined substrate metabolism during exercise in naturally menstruating (NoOC, n = 34) and women using combined oral contraceptives (COC, n = 19).

Methods: Participants were measured in a fasted state in the follicular (FOL) and luteal (LUT) phases, or the inactive (INACT) and active (ACT) phases of COC use. Serum E2 and P4 were assessed using immunoassays and body composition via bioimpedance. Peak fat oxidation (PFO) and FATMAX, the intensity eliciting PFO, were evaluated using indirect calorimetry. FATMAX was calculated using peak oxygen uptake (V̇O2PEAK), measured on the following day.

Results: PFO did not differ between FOL and LUT (0.40 ± 0.09 g·min-1 vs. 0.41 ± 0.10 g·min-1, p = 0.482) or INACT and ACT (0.48 ± 0.12 g·min-1 vs. 0.44 ± 0.11 g·min-1, p = 0.099). FATMAX showed no phase-related variation (NoOC: FOL 47.3 ± 15.7 % vs. LUT 47.7 ± 13.6 %, p = 0.727; COC: INACT 57.1 ± 12.3 % vs. ACT 52.5 ± 12.2 % p = 0.172). PFO was 0.08 g·min-1 (95 % confidence interval: 0.02 g·min-1-0.14 g·min-1, p = 0.010) and FATMAX 9.8 % (95 % CI: 1.0-8.7 %, p = 0.031) higher in the INACT vs. FOL. The difference in PFO persisted after adjusting for fat-free mass and V̇O2PEAK (p = 0.033) but was not significant after excluding an outlier from the COC group (p = 0.108).

Conclusions: PFO and FATMAX remained stable between MC and COC phases, suggesting no need to standardize measurements by cycle phase. However, higher PFO and FATMAX in the COC group during INACT compared to FOL suggests distinct effects of exogenous hormones on metabolism compared to endogenous hormones. Practitioners should consider these differences when assessing factors influencing substrate metabolism.

Purpose: Exercise is widely recognized for providing numerous benefits to prostate cancer (PCa) survivors. Numerous preclinical studies have investigated the role of exercise on tumor progression, but results are often controversial, largely due to variations in experimental protocols.

Methods: In this study, the comprehensive effects of exercise on PCa were evaluated with two different aerobic exercises, forced and structured Exercise Training on treadmill (ET), and Voluntary Wheel Running (VWR). Human PCa PPC-1 cells or PBS were injected into athymic nude mice, randomized into four groups: healthy, cancer control (CaCTL), cancer with exercise training (CaET), and cancer with voluntary wheel running (CaVWR).

Results: ET significantly reduced tumor growth (290.38 ± 75.43 mm3) compared to CaCTL mice (374.84 ± 86.15 mm3, p = 0.0227). ET also regulated plasma IL-6 concentration, protected against cancer-induced adipose tissue loss (CaCTL = 171.21 ± 86.73 mg; Ca ET = 341.71 ± 137.24 mg, p = 0.0295) and preserved strength (CaCTL = 126.53 ± 6.68 g; CaET = 137.32 ± 6.39 g, p = 0.0018). However, ET did not protect against cancer-induced muscle mass loss (CaCTL = 175.06 ± 18.07 mg; CaET = 181.41 ± 14.59 mg). In contrast, VWR did not provide similar benefits on the assessed cancer-related outcomes, aside from preserving muscle strength (CaCTL = 126.53 ± 6.68 g; CaVWR = 134.59 ± 7.01 g, p = 0.0204).

Conclusions: ET represented an effective strategy against PCa by limiting tumor growth, but also by mitigating inflammation and adipose tissue loss and preserving muscle strength, whereas VWR only provided limited benefits. The exercise parameters are emerging as a critical factor in combating PCa, warranting further investigation.

Background: Both insufficient physical activity (PA) and excess body weight are important risk factors for cardiovascular disease (CVD), and PA is closely related to body weight. However, it remains unclear whether PA modifies or mediates the association of body mass index (BMI) with CVD.

Methods: We conducted a cross-sectional study of 35,406 adults participating in the National Health and Nutrition Examination Survey (NHANES). The mediation and interaction effects of PA were assessed using a four-way decomposition approach. An additional two-step Mendelian randomization (MR) analysis was performed to verify the potential causal mediation effect.

Results: A strong association was observed between PA and lower odds of CVD after adjusting for all confounders [Odds Ratio (OR): 0.84; 95% Confidence Interval (CI): 0.74-0.95]. Increased BMI was associated with higher odds of CVD (OR: 1.04; 95% CI: 1.03-1.04). PA showed interaction and mediation effects on the association of BMI with CVD. The overall proportion attributable to interaction was -37.5%, while the overall proportion attributable to mediation was 22.2%. MR analysis further confirmed that PA causally mediated the pathway from BMI to CVD.

Conclusions: PA modified the association of BMI with CVD, suggesting that sufficient PA is needed to lower the impact of high BMI on CVD risk. Moreover, we found that PA served as a causal influence on the association of BMI with CVD, indicating that higher BMI led to a lower level of PA, which in turn increased the risk of CVD.

Purpose: Stress is a risk factor for psychiatric illnesses. However, not all individuals exposed to stress will develop affective disorders. We examined whether pretreatment with stress-free voluntary wheel running (VWR) exercise prophylactically enhances stress resilience in rodents and how it can effectively prevent the development of depressive- and anxiety-like behaviors.

Methods: Eight-week-old C57BL6/J mice were housed in cages with VWR and subjected to chronic restraint stress (CRST) for 2 h daily for 14 days. The mice were assessed for depressive- and anxiety-like behaviors, and a behavioral matrix (k-means clustering) was introduced to segregate the mice into susceptible and resilient subpopulations. Chemogenetic inhibition and retrograde tracing were used to map the neural circuits involved in VWR's resilience-enhancing properties.

Results: After CRST exposure, 71.50% of CRST mice with VWR were stress resilient, with less stress-induced prolonged activation of the hypothalamic-pituitary-adrenal (HPA) axis and corticosterone (CORT) response, representing a 57.20% increase compared with CRST-only mice. Staining for c-Fos showed that VWR activated predominantly hippocampal GABAergic neurons and suppressed the activity in the medial prefrontal cortex (mPFC). Chemogenetic inhibition of the ventral hippocampus (vHPC) dissipated the antidepressant and anxiolytic effects of VWR pretreatment. In addition, the nucleus reuniens (NR) was implicated in VWR's resilience-enhancing properties, relaying reciprocal interactions of the mPFC-vHPC pathway.

Conclusions: These findings suggest that stress-free voluntary exercise may be an effective modality for stress management and warrant further investigation into its resilience-enhancing mechanisms.

Purpose: The aim of the present study was to compare performance and physiological effects, and inter-individual response variation in performance and its physiological determinants between heart rate-based (HR), race pace-based (RP) and heart rate variability-based (HRV) training prescription approaches in recreational distance runners.

Methods: Twenty-eight participants completed a 6-week endurance training intervention after being randomly assigned to three groups: HR (n = 9), RP (n = 9), and HRV (n = 10) training prescription approaches.

Results: No interaction effects between groups were observed. Main time effects were found for absolute and relative V̇O2max, running economy (RE), speeds associated to the first (sVT1) and second ventilatory thresholds (sVT2) and 7 km time trial performance (TT) (p < 0.001, 0.88 ≤ d ≤ 2.67). The RP group improved TT (p < 0.05, ES = 1.07), showing greater effectiveness in enhancing maximal aerobic speed and fat mass reduction, but did not consistently improve physiological parameters like sVT2 or RE. The HRV method increased sVT2 (p < 0.01, ES = 1.34) and was more successful in boosting sVT1 and V̇O2max, although it resulted in an increase in fat mass. Training load was similar between groups (p > 0.05), and a pyramidal training intensity distribution model was found in all groups. The lowest inter-individual response variation in TT was found in the RP group (coefficient of variation [CV] = 0.82), whereas the HRV group demonstrated a lower variation in relative V̇O2max (CV = 0.75) and sVT2 (CV = 0.79).

Conclusions: The RP approach is an effective and useful training prescription method for optimising performance in recreational runners, while the HRV method proves valuable for enhancing key physiological markers.