Medicine and Science in Sports and Exercise最新文献

Purpose: Sleep deprivation and elevated blood pressure (BP) increase the risk of cardiovascular diseases. However, the effects of sleep deprivation on BP response, especially at exercise onset remain unclear. We aimed to elucidate the effects of experimental sleep deprivation (ESD) on resting and exercise BPs, including that at exercise onset, and investigate whether a night-time nap during ESD changes the ESD-altered BP.

Methods: Twelve healthy young men underwent 2-min submaximal isometric elbow flexion (IEF) exercise to measure BP after 7 days of normal sleep (control trial), 24-h ESD (ESD trial), and ESD with a 2-h night-time nap (ESD + NAP trial), which were randomly performed.

Results: ESD significantly elevated the mean arterial pressure (MAP) at rest (85.8 ± 8.0 to 93.3 ± 5.1 mmHg, P = 0.003) and at the last minute of IEF (116.9 ± 13.0 to 126.2 ± 11.8 mmHg, P = 0.003) compared with that observed in the control trial. At IEF onset (the initial 15 s), ESD significantly elevated the MAP (88.7 ± 12.6 to 103.1 ± 8.8 mmHg, P < 0.001) and augmented the MAP responsiveness from baseline, compared with that observed in the control trial (Δ2.9 ± 11.4 to Δ9.8 ± 6.6 mmHg, P = 0.017). The MAP responsiveness in the ESD + NAP trial (Δ7.3 ± 5.2 mmHg) was not significantly different from that in the control trial (P = 0.165) and the ESD trial (P = 0.129).

Conclusions: ESD significantly elevated both resting BP and the BP during submaximal isometric exercise and significantly augmented the initial pressor response to the exercise. A 2-h night-time nap during ESD appears to be insufficient to completely attenuate ESD-induced augmented pressor responses.

Purpose: Eccentric calf training for Achilles tendinopathy shows variable success in athletes. Recent insights suggest a role for tendon fluid flow (exudation or redistribution) during exercise, which explains post-exercise reductions in thickness and increases in stiffness of the tendon. This fluid flow is thought to be beneficial as it may promote tendon remodeling, reduce intratendinous pressure, and alleviate pain. In this perspective, slow, high-load exercises are promoted as they theoretically facilitate tendon fluid flow. However, evidence supporting this assumption is lacking. Therefore, this study aimed to investigate whether loading speed and intensity during eccentric calf training impact acute changes in midportion Achilles tendon thickness and stiffness, reflecting alterations in local tendon fluid content.

Methods: A randomized, assessor-blinded, crossover trial was conducted with 34 healthy athletes (17 men, 17 women, age: 23.7 ± 6 years). Participants underwent 3 single-leg eccentric heel-drop interventions with 20% additional bodyweight, varying in loading speed (fast: 1 s, slow: 3 s) and loading intensity (low: to plantigrade, high: to maximal dorsiflexion). Achilles tendon anteroposterior diameter (APD), cross-sectional area (CSA), and shear-wave velocity (SWV) were assessed in the midportion region using ultrasonography and shear-wave elastography pre-and immediately post-intervention.

Results: The slow, high-load intervention produced greater immediate reductions in tendon APD and CSA (8.7% and 10.1%), compared to the slow, low-load (4.0% and 4.7%) and fast, high-load (2.9% and 3.4%) interventions (p < 0.001). Moreover, only the slow, high-load intervention increased tendon SWV (52.4%, p < 0.001).

Conclusions: These findings provide the first evidence that both loading speed and intensity during eccentric calf training impact acute changes in Achilles tendon thickness and stiffness, likely mediated by changes in fluid flow, which could be relevant for tendinopathy rehabilitation.

Purpose: COVID-19 is an independent risk factor for cardiovascular disease. The aim of this study is to determine the burden, characteristics, and causes of sudden death in sport (SrSD) before and after the COVID-19 pandemic in the general population.

Methods: Retrospective observational study. Autopsied SrSD studied in Catalonia were consecutively included. Two periods were considered: Before lockdown (January 2019-March 2020) and after lockdown (March 2020-December 2021). Initial care variables and causes of death were collected. Periods were compared, and logistic regression analyses were performed.

Results: A total of 156 SrSD were collected, with no differences in the incidence between the study periods. Of the cases, 98.7% were male, with a mean age of 55.8 years (SD 12.1). Cycling was practised by 40.0%. Coronary artery disease was the leading cause of death, with no difference before and after lockdown. No cases of myocarditis were described. Of the total number of SrSD, 98 (62.8%) received a CPR attempt. After lockdown, the SrSD that occurred in country areas decreased (40.6% vs 24.4 %, p = 0.032), the rate of CPR attempts (54.3% vs 69.8%, p = 0.034) and hands only CPR increased (76.6% vs 57.9%, p = 0.048).

Conclusions: There were no changes in the burden and causes of SrSD before and after the COVID-19 lockdown. Differences were found in the SrSD initial care received due to the change of basic life support recommendations and the sport activity habits.

Abstract: Physical activity is frequently touted as beneficial for mental health. This paper, based on a 2023 ACSM colloquium, highlights key strengths and limitations of the evidence regarding physical activity and mental health from three perspectives: epidemiological studies, randomized controlled trial experiments, and investigations that explicitly consider the potential role that contextual factors, such as the social climate in which physical activity is completed, can play in physical activity-mental health interactions. A large body of epidemiological evidence supports that regular leisure time physical activity is associated with less depression and anxiety. Higher amounts of physical activity are often associated with fewer depressive symptoms, but there may be a dose-response point where for some people more is not better but can plateau or even worsen. Epidemiological evidence is emerging but currently inadequate to support associations between mental health and occupational, transportation/active commuting or domestic/household physical activity types. A large body of randomized controlled trials, typically small, short duration and conducted with samples biased toward middle-to-higher socioeconomic status Whites, supports that the adoption of regular exercise improves aspects of mental health; however, the mechanisms are unclear and for those without mental disorders the mean effects are small. Mental health benefits of exercise may be partially a placebo response or result from contextual factors surrounding exercise. A small body of evidence supports that contextual elements, such as the program implementation quality and social environment, can influence the mental health outcomes associated with physical activity programs, but the evidence is currently inadequate to identify which contextual variables have consistent moderate or larger effects. Greater progress will be made in this area when research designs are expanded to include consideration of the potential influence of contextual factors on relationships between physical activity and mental health.

Exercise in warm environments increases thermal/cardiovascular strain and decreases gastrointestinal (GI) integrity and endurance performance. However, laboratory-based studies have provided little to/no facing airflow, potentially exacerbating these effects, particularly for cycling, where convective cooling may be a major contributor to thermal balance.

Purpose: This study investigated the effect of cycling in a warm vs temperate environment with sufficient facing airflow on exogenous glucose use, performance, and GI responses.

Methods: Ten trained male cyclists/triathletes (36 ± 6 y; 55 ± 6 mL/kg/min) completed V̇O2peak and familiarisation trials, and two experimental trials in 19 °C (TEMP) and 32 °C (WARM). Experimental trials involved 2 h cycling at ~50% Wpeak (preload) and an ~15 min time trial (TT) with fan-provided airflow covering the cyclist (preload: ~29 km/h, TT: ~35 km/h). A glucose drink containing [U-13C]-glucose was consumed every 20 min during the preload (72 g/h).

Results: Average 40-120 min (TEMP 0.56 ± 0.13 g/min; WARM 0.48 ± 0.12 g/min; 15%; P = 0.015) and peak (TEMP 0.79 ± 0.18 g/min; WARM 0.68 ± 0.14 g/min; 14%; P = 0.008) exogenous glucose oxidation were reduced in WARM. TT performance was 15% slower in WARM (TEMP 819 ± 47 s; WARM 961 ± 130 s; P = 0.002). GI temperature (P = 0.007), heart rate (P < 0.001), and RPE (P = 0.046) were greater during WARM. GI comfort (P = 0.659) and Intestinal Fatty Acid Binding Protein (IFABP) (P = 0.094) were not different between trials.

Conclusions: These data demonstrate that ability to use glucose provided in drinks was impaired during prolonged cycling in WARM. WARM ambient conditions impaired laboratory-based cycling performance, even with facing airflow approximating outdoor conditions, likely via impairments of thermoregulatory, cardiovascular, and metabolic function.

Purpose: While weight-bearing physical activity (PA) benefits bone health, it remains unclear whether PA can counteract hormone-driven menopausal bone deterioration. This secondary analysis of a population-based prospective follow-up study examined changes in bone health indicators around menopause and evaluated whether accelerometer-measured habitual skeletal loading is associated with these changes.

Methods: A total of 189 initially perimenopausal women without estrogen therapy (mean age 52 [SD 2] years) were followed until they became postmenopausal (mean follow-up time 15 [9] months). Femoral neck bone mineral density (FN BMD) and bone mineral content (BMC) were measured with dual x-ray absorptiometry (DXA). Femoral and tibial shaft volumetric BMD (vBMD), cross-sectional geometry, and stress-strain index (SSI) were assessed using quantitative computed tomography (QCT) in a subset of 61 women. Habitual skeletal loads (mean daily osteogenic index [OI] and low, medium, and high-intensity impact counts) were evaluated with multiple-day free-living accelerometry records. Longitudinal associations of habitual skeletal loads and bone outcomes were analyzed with GEE models.

Results: Consistent decreases were observed in FN BMD and BMC, and femoral and tibial shaft vBMD and SSI (p < 0.001) over the follow-up. Slight decreases over the follow-up were also observed in OI and medium impacts in the full sample, and medium and high impact counts in the subsample (p < 0.05). Medium impacts were associated with tibial shaft vBMD and SSI (β = 0.204, 95% CI [0.018, 0.391] and β = 0.077 95% CI [0.000, 0.154], respectively). High impacts were associated with femoral shaft vBMD (β = 0.186 95% CI [0.006, 0.366]. However, no association was observed between habitual skeletal loads and changes in bone characteristics over the follow-up.

Conclusions: We observed a rather uniform skeletal response to the menopausal transition at all measured bone sites. Positive associations were found between medium and high-intensity impacts and bone characteristics at the femoral and tibial shafts. However, habitual skeletal loading did not seem to counteract bone deterioration during the menopausal transition.

Purpose: This study investigated the mechanisms of neuromuscular fatigue and recovery in quadriceps and hamstring muscles following soccer match-play and typical training sessions dedicated to the physical development of players.

Methods: Fifteen male professional academy soccer players completed at different visits a 90-minute simulated soccer match-play (MATCH) and four training sessions modulating the metabolic nature (HIIT vs. SPRINT) and the mechanical load (number of changes of direction [COD]). Neuromuscular fatigue was evaluated via changes in pre to postexercise maximal voluntary contraction (MVC), potentiated twitch force (PTw, peripheral fatigue) and voluntary activation (VA, central fatigue) evoked by electrical stimulation in quadriceps and hamstring muscles. External load was assessed via GPS units.

Results: Following MATCH, ΔMVC was similar between quadriceps (-18.3 ± 11.6%) and hamstring (-23.2 ± 10.6%) muscles. However, hamstring muscles displayed greater ΔPTw (-27.2 ± 25.0% vs. -17.2 ± 10.9%), but lower ΔVA (-8.2 ± 14.0% vs. -18.1 ± 12.7%) than quadriceps muscles. Quadriceps and hamstring muscles fatigue recovered 24 h post-match. Increasing the mechanical load (number of COD) increased the magnitude of neuromuscular fatigue in quadriceps but not in hamstring muscles. Modulating the metabolic nature of the session (SPRINT vs. HIIT) did not influence neuromuscular fatigue in either muscle group. No correlation was found between ΔMVC and a fatigue index derived from GPS metrics for any muscle groups (r2 < 0.06, P > 0.38).

Conclusions: The magnitude and etiology of neuromuscular fatigue were modulated by the muscle group investigated and the mechanical load of the exercise task. Moreover, the 'fatigue index' derived from GPS metrics is not a valid surrogate of neuromuscular fatigue on the field.

Purpose: To examine movement behaviour with stress-related biomarkers alongside self-reported mental health issues in adolescents with Neurodevelopmental disorders.

Methods: One hundred fifty-one adolescents with clinically diagnosed NDD and aged between 12-17 years were recruited in Hong Kong secondary schools. Salivary cortisol as a stress-related biomarker and self-reported mental health variables including anxiety, depression, and stress were collected. PA levels (light PA [LPA], moderate PA [MPA], moderate-to-vigorous PA [MVPA], and vigorous PA [VPA]) and sedentary behaviour [SB] were measured using a tri-axial waist-worn accelerometer. Data were analyzed using bootstrapping regression models (bias-corrected method), adjusted for age, gender, and body mass index (BMI).

Results: A significant negative association between MPA and MVPA with self-reported stress and a negative association between MVPA and self-reported anxiety were observed in adolescents with ADHD. A significant positive association between SB and salivary cortisol and a negative association between VPA and salivary cortisol in adolescents with comorbid ASD-ADHD was observed.

Conclusions: Study results demonstrated the association of PA levels and SB with mental ill-being including stress-related biomarkers in both adolescents with ADHD and comorbid ASD-ADHD. Participation in PA, in particular at MVPA intensity, may be essential for mitigating mental health issues in this population. Alternatively, our results could show that mitigating stress and mental health issues is critical for PA participation in adolescents with NDD.