European journal of sport science最新文献

This study examines the associations between force and velocity characteristics of forward skating and off-ice speed, agility, and power of highly trained teenage ice hockey players. Players attending the Quebec ice hockey federation's off-season evaluation camp were invited to participate in this study. Final sample consists of 107 highly trained teenage ice hockey players (Males: n = 38; 13.83 ± 0.38 years; Females: n = 69: 14.75 ± 0.90 years). Individual force–velocity profiles (F–V) were determined during a 44 m skating sprint. Off-ice speed, agility, and power were measured using 30 m sprint, 5-10-5 agility, and standing long jump. Associations between F–V mechanical capabilities and off-ice indicators were analyzed with correlational analyses and multivariate analysis of covariance (MANCOVA). Results of pooled data indicate that the three off-ice measures had moderate associations with F₀ and V₀ and large associations with P_max. Associations with Rf_max, D_rf, and S_fv were moderate to small. F₀ had stronger associations with off-ice performance in female players while V₀ was more important with male players. MANCOVA identified 5-10-5 times as the better predictor for F₀ while 30 m sprints times better predicted V_0. To maximize physical attributes of skating ability, practitioners are encouraged to focus on a general physical preparation for highly trained teenage players. Prioritizing types of exercises that use change of direction or acceleration and linear speed should have distinct effects on F₀ and V₀ on the ice.

One marker of expertise in sport is athletes' ability to anticipate future events. In the 4 × 100 m relay, these anticipation skills are an essential asset for initiating their run at the right time. However, no study has focused on describing the underlying perceptual-motor processes involved. Virtual reality provides powerful tools to describe and understand these processes, overcoming the drastic constraints encountered in the real world. Nineteen athletes from the French national teams were immersed in a digital replica of the Stade de France and confronted with digital twins of potential partners based on motion capture. Their task was to initiate their run exactly when their virtual partner passed over a go-mark placed on the ground. The timing of different body motor events and visual behavior were measured and analyzed. Results showed that the execution of this highly constrained task is the result of a significant reduction in the variability of motor events preceding the start. These findings reveal the implementation of a perceptual-motor dialog until the initiation of the run. This study is a first step toward understanding the mechanisms underlying anticipation skills in the 4 × 100 m relay; it constitutes a preliminary step to the deployment of VR training protocols.

It is known that microtrauma exists in the thigh muscles after long-distance running such as the half-marathon. Moreover, training characteristics of long-distance runners may influence the specificity of the distribution of muscle fiber types in the thigh and affect muscle responses to lipid metabolism. However, the specific changes in microtrauma and intramuscular lipid in thigh muscles after a half-marathon are unknown. A cohort of 20 healthy recreational marathon runners was recruited to complete a half-marathon. MRI T2 mapping and 6-echo q-Dixon sequences were employed at baseline (P1), 2–3 h after running (P2), and 1 day after running (P3). Inflammatory markers (the T2 values) and intramuscular fat fraction (the proton density fat fraction, PDFF) were measured in thigh muscles to detect microtrauma and intramuscular lipid changes, respectively. One-way analysis of variance showed significant time effects for T2 values and PDFF. Post hoc analysis of the 14 datasets collected at three time points revealed significantly higher T2 values in all thigh muscles after running (all p < 0.05). Significant differences in T2 values persisted for all thigh muscles at P3 compared to P1 (all p < 0.05). The PDFF of the vastus lateralis and vastus medialis was significantly decreased at P2 compared to P1 (p < 0.05). No significant differences in PDFF were observed for the thigh muscles at P3 compared to P1. The manifestations of inflammation edema and intramuscular lipid investigated through MRI may offer valuable insights for recreational marathon runners regarding the lower limb movement characteristics during half-marathon running.

We examined the sensitivity and time-course of recovery of neuromuscular and perceptual player monitoring measures to U-18 English Premier League academy football match play. Eighteen players performed maximal posterior chain, hip adductor and abductor isometric strength tests, countermovement jumps (CMJ) and provided self-report wellbeing scores around eight competitive league home games: 1 day before (MD-1), pre-match (MD-PRE), post-match (MD-POST) and two (MD+2) and three (MD+3) days post-match. A permutational multivariate analysis of variance and post hoc univariate analyses of variance were used to examine match-induced responses to monitoring variables. Between MD-1 and MD-POST, we observed small to moderate reductions to the adductor and abductor peak force and maximal impulse and IPCS peak force; small reductions to CMJ jump height (JH) (flight time), eccentric peak force and eccentric deceleration rate of force development and moderate to large reductions to perceived fatigue, muscle soreness and mood. No match-induced changes were observed for CMJ flight time: contraction time or eccentric duration. Posterior chain, abductor, CMJ and self-report measures normalised by MD+3 but adductor peak force remained compromised at MD+3 (ES = small). Posterior chain, adductor and abductor peak isometric force and maximal impulse; CMJ JH, eccentric peak force and eccentric deceleration rate of force development and perceived fatigue, muscle soreness and mood are sensitive to match-induced fatigue. Since adductor peak force remained compromised at MD+3, it is apparent that players might not achieve complete neuromuscular recovery within 3 days of match play, and that the adductor muscle group might be particularly vulnerable to match-induced fatigue.

Montmorency cherry (MC) can improve endurance performance, but optimal pre-exercise timing of supplementation and influence of training status on efficacy are unknown. We investigated the effect of MC concentrate ingestion between 30- and 150-min pre-exercise in trained and recreational cyclists on 15-km time trial (TT) performance and exercise economy. Twenty participants (10 recreationally active, RA; 10 trained, T) completed 10 min of steady-state exercise (SSE) at 40%Δ (SSE) and a TT on four separate occasions following an unsupplemented (US), 30-, 90- or 150-min pre-exercise Montmorency cherry concentrate (MCC) supplementation conditions (MCC^30/90/150min). Venous and capillary blood samples were taken at regular intervals pre- and post-SSE and TT. MCC significantly improved TT performance, but not exercise economy. The greatest improvement in performance occurred following MCC^90min compared to US (US 1603.1 ± 248 s vs. MCC^90min 1554.8 ± 226.7 s, 2.83% performance improvement). Performance was significantly enhanced for trained (US 1496.6 ± 173.1 s vs. MCC^90min 1466.8 ± 157.6 s) but not recreationally active participants. Capillary [lactate] and heart rate were significantly greater during the TT for the 90-min dose timing (p < 0.05). In the MCC^30min and MCC^90min conditions, plasma ferulic (US 8.71 ± 3.22 nmol. L⁻¹ vs. MCC^30min 15.80 ± 8.69 nmol. L⁻¹, MCC^90min 12.65 ± 4.84 nmol. L⁻¹) and vanillic acid (US 25.14 ± 10.91 nmol.L⁻¹ vs. MCC^30min 153.07 ± 85.91 nmol. L⁻¹, MCC^90min 164.58 ± 59.06 nmol. L⁻¹) were significantly higher pre-exercise than in US and MCC^150min conditions (p < 0.05). There was no significant change in muscle oxygenation status or plasma nitrite/nitrate concentration. MCC supplementation enhanced endurance exercise performance optimally when consumed ∼90 min pre-exercise producing maximal plasma phenolic metabolites during exercise. The ergogenic effect was greater for trained participants.

Endurance athletes fail to meet carbohydrate (CHO) guidelines for competition, which may be due to limited knowledge. However, the relationship between knowledge and practice in this population is unknown. To investigate this, we assessed the dietary intake in 50 athletes (37 females) who completed endurance events ≥2.5 h in duration and compared CHO intake against the carbohydrates for endurance athletes in competition questionnaire validated nutrition knowledge questionnaire, with specific questions related to CHO loading, pre-competition meal and during-competition intake. CHO-loading guidelines (10–12 g · kg⁻¹ · day⁻¹) were met in practice by n = 5 (10%), but there was no relationship between identified requirements (range 0–12 g · kg⁻¹ · day⁻¹) and actual intake (r_s = 0.133, p = 0.358), with the n = 18 (36%) who correctly identified requirements, ingesting 6.1 ± 1.9 g · kg⁻¹ · day⁻¹. CHO intake for pre-competition meal guidelines (1–4 g · kg⁻¹) was met in practice by n = 40 (80%), but there was no relationship between identified requirements (range 0 to >4 g · kg⁻¹) and actual intake (r_s = 0.101, p = 0.487), with n = 19 (38%) who correctly identified guidelines requirements, ingesting 1.4 ± 0.6 g · kg⁻¹. CHO intake during-competition guidelines (60–90 g · h⁻¹) was met in practice by n = 18 (36%), but there was no relationship between the amounts of CHO required (range 30 to >90 g/h) and actual intake (r_s = 0.028, p = 0.849), with n = 32 (64%) who correctly identified guidelines requirements, ingesting 56 ± 20 g · h⁻¹. Results show no relationship between the knowledge of CHO recommendations and practice, suggesting that theoretical knowledge does not guarantee the achievement of best practice and other important factors may ultimately determine practice.

Recently, AI-driven skeleton reconstruction tools that use multistage computer vision pipelines were designed to estimate 3D kinematics from 2D video sequences. In the present study, we validated a novel markerless, smartphone video-based artificial intelligence (AI) motion capture system for hip, knee, and ankle angles during countermovement jumps (CMJs). Eleven participants performed six CMJs. We used 2D videos created by a smartphone (Apple iPhone X, 4K, 60 fps) to create 24 different keypoints, which together built a full skeleton including joints and their connections. Body parts and skeletal keypoints were localized by calculating confidence maps using a multilevel convolutional neural network that integrated both spatial and temporal features. We calculated hip, knee, and ankle angles in the sagittal plane and compared it with the angles measured by a VICON system. We calculated the correlation between both method's angular progressions, mean squared error (MSE), mean average error (MAE), and the maximum and minimum angular error and run statistical parametric mapping (SPM) analysis. Pearson correlation coefficients (r) for hip, knee, and ankle angular progressions in the sagittal plane during the entire movement were 0.96, 0.99, and 0.87, respectively. SPM group-analysis revealed some significant differences only for ankle angular progression. MSE was below 5.7°, MAE was below 4.5°, and error for maximum amplitudes was below 3.2°. The smartphone AI motion capture system with the trained multistage computer vision pipeline was able to detect, especially hip and knee angles in the sagittal plane during CMJs with high precision from a frontal view only.

This systematic review aimed to establish the effectiveness of exercise interventions, alone or in combination with dietary modifications, on working memory (WM) in individuals living with overweight and obesity. A comprehensive literature search was conducted using the Scopus, PubMed, Springer-Link, RefSeek, and Cochrane Library databases to identify relevant publications up to January 18, 2024. Data on participants' characteristics, intervention settings, and key outcomes related to WM were extracted. The quality of the studies was assessed using the PEDro scale. A total of 15 articles met pre-established inclusion criteria, involving participants across nine countries with a range of 12–125 individuals and ages spanning from 6 to 80 years old. Among the studies analyzed, 10 exclusively investigated exercise interventions, whereas five explored the combined effects. Notably, 70% of the exercise interventions (7 out of 10) exhibited positive improvements in WM. Likewise, 60% of the combined interventions (3 out of 5) demonstrated favorable enhancements in WM. No differences were found between the two protocols. Common features between the protocols were identified and described. Both protocols showed favorable and promising effects on WM in this clinical population. Nonetheless, the limited evidence addressing the combination of exercise and diet in the same research approach reduces the generalizability of the findings. This review offers valuable insights for future clinical and research applications in people with overweight and obesity.

The purpose of this study was to analyze the criterion-related validity and the reliability of the standing long jump test (SLJ) for evaluating the lower-body explosive muscular strength in adults. A total of 410 adults participated in this study. Sociodemographic, anthropometric measurements, laboratory lower-body muscular strength tests, and the field-based SLJ were performed. In validity analysis, stepwise regression analysis showed that maximal horizontal power, sex, percentage of body fat, maximal horizontal force, and lean mass were significantly associated with the SLJ distance (R² = 0.78; p < 0.001). Reliability analysis showed significant differences between test–retest in the SLJ test, with an overestimation of the second measurement compared to the first [12.14 ± 14.46 cm, intraclass correlation coefficient (ICC) = 0.94 (0.75–0.97), p < 0.001; Cohen's d = 0.31]. The coefficient of variation (CV) was 7.06% and the minimal detectable change (MDC₉₀) was 29 cm. After a learning period, higher reliability values were found [0.45 ± 1.04 cm, ICC = 1.00 (0.99–1.00); p = 0.001; CV = 0.53 %; MDC₉₀ = 1 cm]. The SLJ test may be a valid tool to assess lower-body explosive muscular strength in the adult population. A learning period may be necessary to provide reliability on the SLJ test.

Since assessing aerobic capacity is key to enhancing swimming performance, a simple and widely applicable technology should be developed. Therefore, we aimed to noninvasively visualize real-time changes in sweat lactate (sLA) levels during swimming and investigate the relationship between lactate thresholds in sweat (sLT) and blood (bLT). This prospective study included 24 university swimmers (age: 20.7 s ± 1.8 years, 58% male) who underwent exercise tests at incremental speeds with or without breaks in a swimming flume to measure heart rate (HR), bLT, and sLT based on sLA levels using a waterproof wearable lactate sensor attached to the dorsal upper arm on two different days. The correlation coefficient and Bland–Altman methods were used to verify the similarities of the sLT with bLT and personal performance. In all tests, dynamic changes in sLA levels were continuously measured and projected onto the wearable device without delay, artifacts, or contamination. Following an initial minimal current response, with increasing speed the sLA levels increased substantially, coinciding with a continuous rise in HR. The speed at sLT strongly correlated with that at bLT (p < 0.01 and r = 0.824). The Bland–Altman plot showed a strong agreement (mean difference: 0.08 ± 0.1 m/s). This prospective study achieved real-time sLA monitoring during swimming, even with vigorous movement. The sLT closely approximated bLT; both were subsequently validated for their relevance to performance.