European journal of sport science最新文献

Female distance runners are at a high risk for chronic energy deficiency (ED). ED during predominantly high-volume and/or high-intensity training phases may compromise performance. The relationship between pre-season energy status and running performance in female runners across a season is unclear. To test if energy status as defined by resting metabolic rate ratio (RMR_ratio) is associated with running performance, female collegiate distance runners (18–25 yr; n = 38) were assessed across 10–12 wks. Energy status, body composition, and 5 km time trial (measure of performance) were assessed pre- and post-competitive season. Runners were categorized at baseline based on pre-season measured-to-Cunningham₁₉₉₁-predicted RMR_ratio: metabolically suppressed (SUP: RMR_ratio < 0.92, n = 12) and energy replete (NSUP: RMR_ratio ≥ 0.92, n = 26). Repeated measures ANOVA tested effects of pre-season RMR_ratio groups, time, and group*time on performance. Linear regression analysis tested whether factors (body composition or total triiodothyronine, TT₃) predicted performance across the season. Twenty-one runners (19.6 ± 0.2 yr, 20.2 ± 0.4 kg/m²) completed pre- and post-season performance runs. Groups had similar body mass, body mass index, percent body fat, and lean body mass. ANOVA revealed a significant group effect of RMR_ratio on running performance, but no effect of time or group*time. SUP had slower 5 km time trial performance compared to NSUP (22.4 vs. 20.4 min, p = 0.04). Controlling for post-season VO₂max, pre-season TT₃ predicted post-season 5 km times (R² = 0.614, p = 0.001). Pre-season energy deficient female runners exhibited poorer running performance during a collegiate competitive season compared to pre-season energy replete runners. Early detection of metabolic compensation in runners may be necessary for optimal performance across a competitive season.

The aim of the study was to evaluate conventional ultrasound (US) as a radiation-free alternative to X-ray for determining biological age (BA; indicated by skeletal age). BA, was determined in 24 healthy, male, elite youth soccer goalkeepers around peak height velocity (11–16 years of age) using both X-ray and conventional US scans of the left hand. X-ray scans were evaluated using the Tanner–Whitehouse 2 method. Conventional US scans served to determine BA via ossification ratios of 13 hand and wrist bones. The new conventional US method showed very strong correlation with X-ray r = 0.90 (p < 0.05). However, the agreement for the difference in BA and CA, which accounts for age-related variance, was classified poor (ICC = 0.48, p < 0.05). Additionally, linear regression analysis and the Bland–Altman plot suggested the presence of a systematic and proportional overestimation of BA in younger players and an underestimation of BA in older players. Furthermore, Cohen's kappa showed a moderate agreement between players' classification into maturity groups for the two assessment methods. In conclusion, our study has shown that using US-derived ossification ratios did not deliver valid results compared to X-ray when determining BA in youth soccer goalkeepers.

This study aimed to examine the acute effects of concurrent muscle strength and sport-specific endurance exercise order on immunological stress responses, metabolic response, muscular-fitness, and rating-of-perceived-exertion (RPE) in highly trained youth female judo athletes. Thirteen female participants randomly performed two concurrent training (CT) sessions; strength-endurance and endurance-strength. Immune response, metabolic response, muscular fitness (i.e., countermovement jump-derived force and power [CMJ-force and CMJ-power]), and RPE were measured at different time points (i.e., PRE, MID, POST, POST6h, and POST22h). There were significant time × order interactions for lymphocytes (p = 0.006, ES = 1.31), granulocyte–lymphocyte ratio (p = 0.002, ES = 1.56), and systemic inflammation index (p = 0.029, ES = 1.11), blood glucose and lactate (p < 0.001, ES = 2.09 and p = 0.0018, ES = 1.51, respectively), CMJ-force (p = 0.033, ES = 1.26), and CMJ-power (p = 0.007, ES = 1.40) as well as RPE (p < 0.001, ES = 2.05). CT-induced acute (i.e., POST) but not delayed (i.e., POST6h and POST22h) order-dependent immune cell count alterations in highly trained youth female judo athletes. All markers of the immune system went back to baseline values at POST22h. Metabolic responses were slightly higher following the endurance exercise (irrespective of the applied exercise order). CMJ-measures and RPE fluctuated during both CT sessions but returned to baseline 6 h post-exercise.

To critically evaluate sport nutrition services available to male and female international rugby unions. Fifteen participants, representing 16 international rugby unions, including nine female and seven male teams (one participant worked with both a female and male union), responded to an online survey. Twelve of the unions recruited were ranked in the top 10 globally by World Rugby. Twelve unions employed accredited nutrition practitioners with significant experience (> 5 years: n = 5; > 10 years: n = 4) and advanced qualifications (master's degrees: n = 8; doctorates: n = 2). Three unions did not employ a qualified nutrition practitioner (female: n = 2; male: n = 1). Full-time employment was more common among nutrition practitioners serving male (n = 4/5) versus female (n = 3/6) unions. Practitioners served male unions for more hours per week (42 ± 28) than female unions (24 ± 20). Practitioners were involved in sport science meetings (n = 14/15), anti-doping education, menu design, strategy development (n = 13/15), body composition assessments, individual consultations (n = 12/15), focusing on fuelling, recovery and injury rehabilitation (n = 14/15). Participants were “moderately confident” (n = 8/15) in using behaviour change techniques. Most participants agreed on the lack of female-specific nutrition guidance (n = 14/15), relying on guidance for male players due to limited evidence (n = 7/9). This study provides the first critical reflection of sport nutrition service delivery within international rugby. The findings highlight gender disparities for female players, with reduced applied support and a lack of female-specific guidelines. Recommendations include enhancing practitioner training in behaviour change, hiring qualified nutritionists, deemphasising body composition assessment, and conducting more research to improve nutrition services, especially for women.

The effects of flywheel (FW) training on jump performance, muscle function, and muscle mass in athletes have not been fully clarified. The purpose of the present study was to evaluate the effects of an 8-week FW training program on jump performance, stretch-shortening cycle (SSC) function, muscle strength, peak power and muscle thickness in collegiate basketball players. Twenty male college basketball players (mean age: 19.8 ± 1.3 years, height: 179.1 ± 6.7 cm, body mass: 72.9 ± 6.3 kg) were randomly assigned to either the FW training (n = 11) or control group (n = 9). The FW training group performed squat exercises, 5 sets of 8 repetitions, twice a week using the FW device. Baseline and post-training assessments of jump heights of squat jumps (SJs), countermovement jumps (CMJs), and drop jumps (DJs) were performed in both groups. Additionally, the reactive strength index (RSI), representing SSC function; isometric maximum voluntary contraction (MVC) torque during knee joint extension; peak power during squats; and quadriceps muscle thickness were evaluated. As the results, we observed that the FW training group demonstrated significant increases in post-training SJ height (15.1%, p = 0.03), DJ height (23.2%, p = 0.01), RSI (36.8%, p = 0.04), MVC, peak power and muscle thickness compared with pre-training levels. Furthermore, between-group comparisons indicated significantly higher post-training SJ height, DJ height, RSI, MVC, peak power, and muscle thickness in the FW training group (p < 0.05). Therefore, the FW training program effectively enhanced jump performance and SSC function in male basketball players and proved beneficial for muscle strength and hypertrophy.

This study aims to determine the validity of the linear critical power (CP) and Peronnet models to estimate the power output associated with the second ventilatory threshold (VT2) and the maximal aerobic power (MAP) using two-time trials. Nineteen recreational runners (10 males and 9 females and maximum oxygen uptake: 53.0 ± 4.7 mL/kg/min) performed a graded exercise test (GXT) to determine the VT2 and MAP. On a second test, athletes performed two-time trials of 9 and 3 min interspaced by 30 min. The CP was determined from the linear CP model and compared with the power output associated with the VT2. The MAP was determined from the linear Peronnet model, established at 7 min, and compared with the MAP determined in the GXT. The CP model was valid for determining the VT2, regardless of sex (p = 0.130; 9/3 vs. GXT: 3.5 [−1.1 to 8.2] W). The MAP was overestimated (p = 0.015) specifically in males (9/3 vs. GXT: 9.2 [3.3 to 15.1] W) rather than in females (p = 9/3 vs. GXT: 1.7 [−4.4 to 8.0] W). Therefore, MAP estimates were determined introducing the CP and W' parameters to a stepwise multiple linear regression analysis. For females, the CP was the unique significant predictor of MAP (p < 0.001) explaining 96.7% of the variance. In males, both CP and W' were significant predictors of MAP (p < 0.001) explaining 97.7% of the variance. Practitioners can validly estimate the VT2 and MAP through a practical testing protocol in both male and female recreational runners.

Some technical limitations to using the eccentric mode to measure peak eccentric strength of the hamstrings (PTH_ecc) were raised. PTH_ecc also has limited validity to predict performance or injury risk factor. Therefore, our aim was to compare PTH_ecc and other isokinetic variables tested in the eccentric and passive modes. Twenty male hockey players (20.2 ± 1.1 years; 179.7 ± 6.9 cm; 73.4 ± 7.1 kg and 12.2 ± 3.4% of body fat) performed maximal eccentric contractions of the hamstrings at 60°·s⁻¹ (three repetitions) and 180°·s⁻¹ (five repetitions) on both legs and using the eccentric mode and the passive mode (automatic movement of the lever arm) of the Biodex System 4 isokinetic dynamometer. The following variables were measured: PTH_ecc, the angle of peak torque (APT,°), angle-specific H_ecc torque at intervals of 10° and the rate of torque development (RTD) in the first 50 ms and the first 100 ms. The main results showed that compared to the eccentric mode, the passive mode led to a significantly greater PTH_ecc in the non-dominant leg only and significantly smaller APT, RTD and angle-specific H_ecc at angles close to knee flexion. In contrast, significantly greater angle-specific H_ecc was observed in the passive mode at angles close to extension (10°–40°). This suggests that, although eccentric or concentric modes can be used to compare isokinetic data to existing literature, it is preferable to use the passive mode to assess peak torque or torque close to knee extension. The eccentric mode might be better to assess variables at the start of movement such as RTD.

This study examines the acute effects of post-activation performance enhancement (PAPE) with different loads (84% and 60% 1-RM) and exercises (hip thrust; HT and glute bridge; GB) on sprint performance (SP) and horizontal force–velocity (HF–V) profile components in adolescent male soccer players. The participants were randomly assigned to three groups: hip thrust group (HTG; n = 13), glute bridge group (GBG; n = 13), and control group (CG; n = 14). Sprint tests at distances of 10, 20, and 30 m were conducted pre-PAPE and post-PAPE protocols with a 7 min rest period. HTG and GBG executed HT and GB exercises at 84% and 60% of their 1-RM loads. Hedge's g was computed to assess within-group (pre-PAPE vs. post-PAPE) comparisons (Within-ES) and between-group (post-PAPE protocols) comparisons (Between-ES). PAPE protocols at 84% and 60% 1-RM loads demonstrated moderate effects on F0_rel, P_maxrel, FV_slope, and D_RF and small effects on V₀, RF_max, and S_20m in both HTG and GBG. Conversely, the CG exhibited trivial effects across parameters. Compared to the HTG 84% 1-RM protocol, the GBG 84% 1-RM protocol showed small effects on V₀ and S_10m. The HTG 60% 1-RM protocol had a small effect on RF_max compared to both GBG 84% and 60% 1-RM protocols. Both HTG and GBG 84% and 60% 1-RM protocols demonstrated small effects on S_30m compared to the CG. These findings suggest that GB exercises may offer a viable alternative to HT exercises for eliciting PAPE effects, particularly in enhancing SP and related mechanics in adolescent soccer players.

Executive functioning (EF) in referees is associated with their decision-making during a match and can be affected by mental fatigue (MF), a psychobiological state induced by prolonged periods of cognitive activity or high cognitive demand within a short timeframe. Therefore, the aim of this study was to investigate the impact of MF on EF and the perception of effort during a physical task for football referees. Twelve male professional football referees were recruited (32 ± 7.3 years; 1.75 ± 0.06 cm; 85 ± 13.32 kg; 41.4 ± 5.92 mL kg^-1 min^-1 VO2max), visiting the laboratory on three occasions: one for characterization and familiarization and two experimental manipulations: high cognitive load (MF) and low cognitive load. After manipulations, they performed a physical task designed to replicate the physical demands of an official match. During the physical task, executive functioning was tested with a reaction time task and the ratings of perceived effort were assessed using subjective scales. The results revealed no effect of MF on response time performance (p = 0.395). However, higher perceptions of effort were observed in the high cognitive load condition (p = 0.018), which may impact physical performance. Despite the alteration in the perception of effort due to mental fatigue, executive function performance of football referees remained unimpaired.