English Institute of Sport

To assess the impact of cardiorespiratory fitness (CRF) and muscle strength on depression and individual depression symptoms. Mendelian randomisation (MR) analysis was conducted in up to 341,326 participants of European ancestry from UK Biobank (aged 37-73years). Genetic variants from previous genome-wide association studies (GWAS) of CRF and grip strength (to proxy overall muscle strength) were utilised to instrument exposures. A broad depression phenotype based on self-report and hospital records, as well as individual measures of depression symptoms from the Patient Health Questionnaire-9 (PHQ-9) were used as outcomes. Analysis was repeated stratifying by sex and using summary statistics from a major depressive disorder (MDD) GWAS. There was no clear evidence for association between CRF and any depression outcome. There was robust evidence suggesting greater grip was associated with lower odds of broad depression (OR per 0.1kg increase in weight adjusted grip: 0.86, 95% CI:0.80,0.93), as well as the PHQ-9 items appetite changes (OR:0.56, 95% CI:0.49,0.65), and anhedonia (OR:0.79, 95% CI:0.69,0.90), a core symptom of depression. There was also some evidence for associations between greater grip and lower odds of depressed mood (OR:0.85, 95% CI:0.74,0.97), psychomotor changes (OR:0.79, 95% CI:0.64,0.97), fatigue (OR:0.83, 95% CI:0.74,0.93) and concentration problems (OR:0.85, 95% CI:0.74,0.98) in the MR-inverse variance weighted analysis. Effects were mostly driven by stronger associations in females and results replicated in the two-sample MR for MDD. Muscle strength may represent an important modifiable factor for preventing and treating depression and several specific symptoms, including core symptoms such as anhedonia.

In 2024, Major League Baseball released new bat tracking data, reporting swing-by-swing bat speed and swing length measured at the point of contact. While exciting, the data present challenges for their interpretation. The timing of the batter’s swing relative to the pitch determines the point of measurement relative to the full swing path. The relationship between swing metrics and swing outcomes is confounded by the batter’s pitch recognition. We introduce a framework for interpreting bat tracking data in which we first estimate the batter’s intention conditional on ball-strike count and pitch location using a Bayesian hierarchical skew-normal model with random intercept and random slopes for batter. This yields batter-specific effects of count on swing metrics, which we leverage via instrumental variables regression to estimate causal effects of bat speed and swing length on contact and power outcomes. Finally, we evaluate the tradeoff between contact and power due to bat speed by modeling a plate appearance as a Markov chain. We conclude that batters can reduce their strikeout rate by reducing bat speed as strikes increase, but the tradeoff in reduced power approximately counteracts the benefit to the average batter.

Abstract The performance of youth in martial arts arises from complex interactions among anthropometric, neuromuscular, maturational, and cognitive elements. However, it is uncertain whether these performance variables constitute common or discipline-specific latent structures across different martial arts. The study aimed to identify discipline-specific latent performance characteristics in youth martial arts athletes and the influence of anthropometric, neuromuscular, maturational, and cognitive factors on inter-sport variation. One hundred fifteen (n = 115) trained male athletes (age 14.4 ± 1.7 years) from judo, jujitsu, Muay Thai, wrestling, taekwondo and pencak silat underwent standardized evaluations. Principal Component Analysis with Varimax rotation (eigen values ≥ 1.0) showed distinctive component structures for each discipline. The primary component for the entire cohort accounted for 38.4% of the variance, predominantly influenced by skeletal muscle mass (0.91–0.94) and countermovement jump peak force (0.90–0.92), suggesting a common morphology–power basis. Judo, Muay Thai, wrestling, and pencak silat exhibited strength profiles characterized by substantial mass support and forceful grasping and striking with a variance ranging from 30.4% to 45.3%. Taekwondo presented a power-centric framework propelled by explosive lower-limb strength (loadings: 0.96–0.99), while jujitsu revealed a cognitive-motor profile, with inhibitory control and executive processing accounting for 60.3% of the variance. The youth performance in martial arts is supported by a common morphological and power foundation, alongside discipline-specific neuromuscular and cognitive requirements.

Mobility modelling plays a pivotal role in evaluating the performance of Mobile Ad Hoc Networks (MANETs), as the movement patterns of nodes strongly influence routing efficiency, connectivity, and network stability. Existing mobility models, particularly entity and group-based frameworks, have proven useful in simulating various MANET applications but remain limited in capturing the complex movement behaviour characteristic of Search-and-Rescue (SAR) operations in disaster scenarios. This study proposes a realistic hybrid mobility model that integrates the essential features of both entity and group mobility paradigms to better represent the coordinated yet flexible dynamics of SAR teams. Three sets of simulations were performed using the Network Simulator 2 (NS2). The first and second simulations focused on generating and combining existing entity and group mobility patterns using the BonnMotion tool, resulting in two composite models (Real1 and Real2). The third simulation compared these models using AODV and DSDV routing protocols under varying node mobility levels and traffic conditions. Key performance metrics, including relative mobility, node degree, partition count, link duration, packet delivery ratio (PDR), throughput, and average end-to-end delay, were analysed. Results demonstrate that it is feasible to concatenate existing mobility models into a coherent hybrid framework. Among the developed models, Real2 exhibited superior performance in most test conditions, yielding higher PDR, lower delay, and more stable connectivity than its constituent models. These findings confirm that the performance of MANETs is highly dependent on mobility realism. Consequently, selecting a model that accurately reflects the behavioural characteristics of the target scenario is essential for credible MANET performance evaluation in emergency response contexts.

The aim of the study was to identify central determinants of using a 3-year longitudinal evaluation of left ventricular (LV) morphological and functional (global, tissue-Doppler and strain) outcome measures obtained at rest and during both submaximal and maximal exercise in a group of highly trained male youth soccer players (SP) and recreationally active male participants (CON). Once a year for 3years, measurements were obtained in both the SP and CON groups (12.0±0.3 and 11.7±0.2years of age, respectively, at the onset of the study). Cardiac ultrasound measures were used to identify LV morphological indices at rest and functional parameters during submaximal and maximal exercise. Training status (P<0.0001) emerged as the only significant independent predictor of , when considering LV morphological variables. At maximal exercise, early diastolic filling (E) was a significant (P=0.001) predictor of , irrespective of the influence of training status. Training status emerged as the significant predictor of across all models that were developed in this study. Minimal LV structural and functional adaptations at both rest and exercise influence , beyond the impact of training status alone. The broader implication of these findings is that the influence of LV cardiac adaptations on over time is mediated by the stimulus of training; this association occurs independently from the impact of growth and maturation on .

ObjectiveTo examine whether health-related physical fitness mediates the association between fundamental motor skills (FMS) and social functioning in school-age children with autism spectrum disorder (ASD).MethodsA total of 117 school-age children with ASD were recruited from special education schools. FMS were assessed using the Test of Gross Motor Development–3 (TGMD-3). Social functioning was evaluated using the Social Responsiveness Scale–2 (SRS-2), with higher scores indicating greater social impairment. Health-related physical fitness was assessed via body mass index, flexibility (sit-and-reach), muscular strength (handgrip), muscular power (standing long jump), balance (one-leg stance), and vital capacity. Pearson correlation analyses and structural equation modeling with bias-corrected bootstrapping (5,000 resamples) were conducted to test mediation effects.ResultsHigher FMS scores were associated with lower SRS-2 scores, indicating better social functioning (r = −0.312, p < 0.001). Several health-related physical fitness components, particularly handgrip strength and flexibility, were significantly associated with both FMS and social functioning. Structural equation modeling demonstrated a full mediation effect, whereby health-related physical fitness significantly transmitted the association between FMS and social functioning (indirect effect B = −2.111, 95% CI [−3.576, −1.189]), while the direct effect was not significant (B = −0.095, 95% CI [−1.193, 1.274]). Model fit indices indicated an excellent fit.ConclusionHealth-related physical fitness, especially muscular strength and flexibility, appears to be a key mechanism linking motor skill proficiency to social functioning in children with ASD. Interventions that integrate strength and mobility training with motor-skill practice may enhance social outcomes in this population.