European journal of sport science最新文献

Type 2 diabetes mellitus (T2DM) is a metabolic disease characterised by chronic hyperglycaemia, whereas obesity is a major risk factor which increases morbidity and mortality. Treatments that alter white adipose tissue to express a metabolically active brown adipose phenotype in rats may offer adjunct treatment in people with T2DM. To investigate whether inorganic nitrate supplementation from beetroot juice (BJ) alters brown adipose tissue (BAT) fat fraction and activation in humans. Thirteen older adults with T2DM (glycated haemoglobin [HbA1c]: 58 ± 13 mmol·mol⁻¹ and body mass index: 29.1 ± 3.1 kg·m⁻²) completed a double-blind, randomised, balanced and placebo-controlled crossover study. Outcome measures (including BAT fat fraction; activation; plasma [nitrate] and [nitrite]) were assessed before and after 14-day of 140 mL·day⁻¹ BJ containing inorganic nitrate (∼12.4 mmol·L¹) or a placebo (∼0.1 mmol·L¹). Magnetic resonance imaging (MRI) and infrared thermography (IRT) were performed to image supraclavicular BAT following a rested cooling protocol, consisting of 60-min exposure via a cold water (8.1 ± 1.2°C) perfused jacket. Respiratory parameters, including respiratory exchange ratio [RER] and mean skin temperature, were measured during the cooling protocol to confirm participants were not shivering. BJ significantly increased venous plasma [nitrate] and [nitrite] versus placebo (p < 0.001) but did not affect BAT fat fraction (p = 0.650) or activation (p = 0.152). Cooling significantly reduced mean skin temperature in BJ (−0.8 ± 0.7°C) and placebo (−0.6 ± 0.6°C) (p < 0.001) and RER remained representative of nonshivering thermogenesis throughout (0.88 ± 0.05 a.u.). 14-day of nitrate supplementation did not increase BAT fat fraction or activation in older adults with T2DM.

The aim of this study was to compare the adaptive responses to repeated sprint training in heat (RSHT) on exercise performance under temperate conditions between males and females. Active males and females completed 7 weeks of repeated sprint training twice a week in temperate (CON, 20°C, 55% relative humidity (RH), males: n = 12, females: n = 13) or hot (HEAT, 30°C, 60% RH, males: n = 12, females: n = 14) conditions. Before and after training, a repeated sprint ability test (RSA) was performed (10-s cycle sprints with 20-s recovery between sprints, until exhaustion), and aerobic and anaerobic qualities were evaluated in temperate conditions. Thermoregulatory responses were measured on Training 1 and 12 (TR1 and TR12). Sprint number during RSA increased after HEAT from 15 to 21 in males and from 8 to 13 in females (p < 0.001), without significant changes after CON. VO₂peak during an incremental exercise test (+3 ± 1 mL·kg⁻¹·min⁻¹, p = 0.032) and mean power output during a Wingate test (+0.41 ± 0.15 W·kg⁻¹, p = 0.007) increased in all groups. No changes were observed in hematological parameters. In HEAT group only, the change in core temperature (−0.16 ± 0.07°C, p = 0.015), but not skin, and thermal sensation (−1 ± 0, p < 0.001) were lower at TR12 than TR1 in both sexes. No changes were observed in sweat rate or whole-body sweat sodium concentration. Seven weeks of RSHT induced partial heat acclimation and increased the number of repeated sprints performed under temperate conditions in females, to the same extent as in males.

Bullying remains one of the major challenges in education, and physical education (PE) can play a key role in its prevention while promoting students' socio-emotional and motivational development. This study examined the effects of the Prevention Bullying in Physical Education (PREBULLPE) programme and cooperative learning pedagogical practice on social and emotional competencies and student motivation in PE classes. The evaluation of both educational programmes was conducted with a total of 330 primary and secondary school students (aged 11–16 years), divided into three groups: the control group (CG, n = 116, M = 13.24 and SD = 1.92), the cooperative learning experimental group (CL, n = 104, M = 12.98 and SD = 1.79), and the PREBULLPE experimental group (PB, n = 110, M = 13.92 and SD = 1.92). A quasi-experimental design was used, with two time point measurements conducted. The Social and Emotional Competencies Questionnaire (SEC-Q) and the Motivation Questionnaire in PE (MQPE) were used. A paired-samples t-test was applied to evaluate within-group differences, and an analysis of covariance (ANCOVA) was performed to detect possible between-group differences, assuming baseline values as covariates. Results showed that social and emotional competencies improved only with the PREBULLPE programme, although there were no significant differences among groups. Autonomous motivation in PE classes improved in both programmes, showing significant differences from the control group. In conclusion, PREBULLPE is effective in improving socio-emotional competencies and autonomous motivation in PE. Cooperative learning, although not enhancing these competencies, contributes to increasing motivation. These findings highlight the need to implement specific PE programmes to prevent bullying and foster students' holistic development.

Deceleration is a crucial task in multidirectional team sports. However, no research has explored how different end stances impact deceleration performance. This is important due to the multidirectional nature and variance of these directional changes in such sports. This study aimed to compare sprint deceleration capacity between front-facing (FF) and side-facing (SF) end stances using a deceleration threshold methodology to standardize the start point of deceleration. 20 team-sport athletes completed three maximal sprint deceleration trials in three conditions: FF and SF with both preferred leg stance (SF_PREF) and nonpreferred leg stance (SF_NON-PREF). Key metrics of time-to-stop (TTS), distance-to-stop (DTS), average deceleration (DEC_ave), and maximum deceleration (DEC_max) were analyzed using linear mixed models. Results indicated significantly different deceleration profiles between FF and SF conditions with FF decelerations exhibiting greater TTS and DTS but lower DEC_ave and DEC_max compared to SF tasks (p < 0.05). No significant differences were determined between SF_PREF and SF_NON-PREF task conditions (p = 0.64–1.00). Correlation analysis demonstrated high similarity in DTS across tasks (r = 0.87–0.92) but greater divergence in TTS and DEC_ave (r = 0.55–0.88). These findings suggest that deceleration mechanics are task dependent with SF tasks eliciting greater braking demands. Practitioners should consider sport-specific deceleration requirements when designing training interventions.

Research investigating the relationship between sport participation and day-to-day antisocial and prosocial behaviours in adolescents has revealed mixed findings. However, research investigating whether social factors reflective of how sport is facilitated could moderate these relationships has received scant attention. This study examined whether perceived coach or physical education (PE) teacher character–building competency moderated relationships between sport participation and both day-to-day prosocial and antisocial behaviours in adolescents. In a sample of 456 adolescents, coach or PE teacher character–building competency moderated how sport participation was linked with prosocial behaviour and violence. Specifically, there was a significant positive relationship between sport participation and prosocial behaviour when coach or PE teacher character–building competency was perceived high, but this relationship was negated when coach or PE teacher character–building competency was lower. Moreover, when coach or PE teacher character–building competency was perceived low, sport participation was positively associated with violence, but this association was negated when such character-building competency was perceived higher. However, this latter moderating effect became nonsignificant after controlling for gender and sport club involvement. Perceived coach or PE teacher character-building competency was also positively associated with day-to-day prosocial behaviours and inversely associated with day-to-day antisocial behaviours in adolescents. These findings offer valuable insight into how sport participation may contribute to adolescents' day-to-day prosocial and antisocial behaviours, alongside underscoring the importance of fostering sport environments that actively support moral character development.

Vertical jump height estimates the ability to oppose gravity and lower body neuromuscular performance in athletes and various clinical populations. The use of force platforms for measuring jump height is increasingly popular due to technological advancements and the equipment's relative ease of use in various settings. However, when utilizing the force platform, ground reaction force (GRF) data must be processed to calculate jump height. While processing the GRF-time data, several factors could alter the data, leading to inaccurate jump height estimates. These factors include sampling frequency, filtering, cut-off frequencies of the filter, averaging periods of body weight, integration procedures, selection of take-off/landing thresholds, and selection of the gravity constant. These data processing steps can alter jump height estimates, with effects ranging from minor (< 0.5%) to major (> 25%). Despite some guidelines on data processing, there is no consistency in the literature or in practice regarding how the GRF-time data should be processed. Consequently, jump height without specifying the data processing steps may be of limited use to others. The aim of this review was to assist researchers and practitioners in navigating the complexities of data processing to better understand how it influences jump height.

To examine how middle-distance athletes maintain self-paced time trial performance on successive days, 12 national-standard middle-distance specialists performed two self-paced 1500 m time trials on successive days. Following baseline assessment and familiarisation trials, participants (10 male, 2 female, mean age ± SD: 27 ± 7 years, mass: 66 ± 8 kg, height: 1.80 ± 0.08 m, season best 1500 m time: 243.9 ± 18.4 s) performed two 1500 m time trials separated by 24 h on an instrumented treadmill. Internal (respiratory exchange ratio; RER, oxygen uptake, blood lactate concentration, heart rate, session and differential ratings of perceived exertion) and external (speed and time) measures quantified exercise intensity. Step length and frequency were collected from integrated force transducers (1000 Hz). All variables were log transformed before analysis with mixed linear models. The uncertainty (90% confidence interval) of our between-trial differences (trial 2 vs. trial 1) for all measures other than peak and mean RER were equivalent to previously reported measurement errors. Additionally, athletes were ∼2.5 times more likely to perceive greater exertion for time trial two, but with considerable uncertainty around the estimates. National-standard middle-distance specialists maintain 1500 m time trial running performance on successive days without the use of any structured recovery interventions.

The aim of this study was to assess the effect of gaze direction instruction on postural stabilisation and muscle activity during landings after various motor tasks in artistic gymnastics. Eighteen female gymnasts (aged 14.0 ± 2.7 years) performed four different landing tasks: drop landing, backward somersault, forward somersault (SF) and a backward acrobatic series (AS). Gaze was directed either downward or straight ahead during landings. Muscle activity was recorded from six lower limb muscles and postural stabilisation was assessed using dynamic stability indices and time to stabilisation. Results showed a significant effect of motor task on muscle activity and stabilisation, with AS and SF presenting higher stabilisation demands. Gaze direction instruction had limited influence on muscle activation patterns and stabilisation, with limited manifestation in dynamic stability indices. Interactions between gaze and motor task were significant only for sagittal dynamic stability in longer time intervals. These findings suggest that motor task complexity primarily governs landing stabilisation, whereas gaze direction plays a minor role in lower limb muscle activity.

Elite law enforcement and special forces operators around the world have a unique skill set, including some risky methods of entry into a scene of operation. With fast roping being actively utilized by this population, it is important to gain an understanding of the physical demands of the task. Thirty-seven Law Enforcement Officers (LEOs) completed five 20 ft fast rope descents onto a force platform, three in standard uniform (without kit) and two with the additional weight of operational kit (with kit). Additionally, 12 LEOs were also fitted with electromyography on their dominant arm. Landing forces with and without kit showed no significant difference. Participants with hang test time (HTT) < 35s showed significantly poorer Landing Control (LC) when descending with kit (p < 0.01). Landing control played an important role, with peak landing force significantly higher (p = 0.025) in uncontrolled landings. CMJ breaking impulse and rebound jump height are the main physical measurable predictors. However, when adjusting for body weight and kit, only rebound jump height remained predictive with marginal significance (p = 0.06) (R² = 0.45, p = 0.008). The biceps brachii (BB) exhibited greater activation when descending with kit (p = 0.003). However, the extensor carpi radialis exhibited the greatest activation during descents in both conditions (p < 0.003). Landing impact forces were not significantly different between groups, however longer HTT correlated with more controlled descents and reduced landing forces. The ECR was observed to be the muscle with the highest activation on all descents, with only the BB increasing in kit.

The effect of the overload principle in motor skill acquisition is unclear. Hence, the present study examined the effect of the overload principle in general, and in particular how the overload principle can be used to increase transferability to nontrained balance tasks with a high level of similarity at different levels of difficulty. A total of 24 participants were randomly assigned to two training groups: (1) low-difficulty training group and (2) high-difficulty training group. Both training groups completed five training sessions consisting of 25 trials over three weeks and only the level of difficulty of the balance board differed. Both the low and high-difficulty training groups had a significant improvement in balance performance in the specific trained conditions, which supports the specificity principle. Most interestingly, only the high-difficulty training group showed significant positive transfer to balance tasks with lower levels of difficulty. The low difficulty training group did not show significant positive transfer to balance tasks with higher levels of difficulty. These findings support the effect of the overload principle. In conclusion, the present findings demonstrate the superior effect of task-specific balance training, and, most interestingly, the study revealed that training with overload at higher levels of difficulty enhances transferability to similar tasks performed at lower difficulty levels.