The molecular athlete: exercise physiology from mechanisms to medals.

Human skeletal muscle demonstrates remarkable plasticity, adapting to numerous external stimuli including the habitual level of contractile loading. Accordingly, muscle function and exercise capacity encompass a broad spectrum, from inactive individuals with low levels of endurance and strength to elite athletes who produce prodigious performances underpinned by pleiotropic training-induced muscular adaptations. Our current understanding of the signal integration, interpretation, and output coordination of the cellular and molecular mechanisms that govern muscle plasticity across this continuum is incomplete. As such, training methods and their application to elite athletes largely rely on a "trial-and-error" approach, with the experience and practices of successful coaches and athletes often providing the bases for "post hoc" scientific enquiry and research. This review provides a synopsis of the morphological and functional changes along with the molecular mechanisms underlying exercise adaptation to endurance- and resistance-based training. These traits are placed in the context of innate genetic and interindividual differences in exercise capacity and performance, with special consideration given to aging athletes. Collectively, we provide a comprehensive overview of skeletal muscle plasticity in response to different modes of exercise and how such adaptations translate from "molecules to medals."

2024 AHA/ACC/AMSSM/HRS/PACES/SCMR Guideline for the Management of Hypertrophic Cardiomyopathy: A Report of the American Heart Association/American College of Cardiology Joint Committee on Clinical Practice Guidelines.

AIM: The "2024 AHA/ACC/AMSSM/HRS/PACES/SCMR Guideline for the Management of Hypertrophic Cardiomyopathy" provides recommendations to guide clinicians in the management of patients with hypertrophic cardiomyopathy. METHODS: A comprehensive literature search was conducted from September 14, 2022, to November 22, 2022, encompassing studies, reviews, and other evidence on human subjects that were published in English from PubMed, EMBASE, the Cochrane Library, the Agency for Healthcare Research and Quality, and other selected databases relevant to this guideline. Additional relevant studies, published through May 23, 2023, during the guideline writing process, were also considered by the writing committee and added to the evidence tables, where appropriate. STRUCTURE: Hypertrophic cardiomyopathy remains a common genetic heart disease reported in populations globally. Recommendations from the "2020 AHA/ACC Guideline for the Diagnosis and Treatment of Patients With Hypertrophic Cardiomyopathy" have been updated with new evidence to guide clinicians.

Flow-mediated dilation is modified by exercise training status during childhood and adolescence: preliminary evidence of the youth athlete's artery.

Chronic exercise training is associated with an "athlete's artery" phenotype in young adults and an attenuated age-related decline in endothelium-dependent arterial function. Adolescence is associated with an influx of sex-specific hormones that may exert divergent effects on endothelial function, but whether training adaptations interact with biological maturation to produce a "youth athlete's artery" has not been explored. We investigated the influence of exercise-training status on endothelium-dependent arterial function during childhood and adolescence. Brachial artery flow-mediated dilation (FMD) was assessed in n = 102 exercise-trained (males, n = 25; females, n = 29) and untrained (males, n = 23; females, n = 25) youths, characterized as pre (males, n = 25; females, n = 26)- or post (males, n = 23; females, n = 28)-predicted age at peak height velocity (PHV). Baseline brachial artery diameter was larger in post- compared with pre-PHV youths (P ≤ 0.001), males compared with females (P ≤ 0.001), and trained compared with untrained youths (3.26 ± 0.51 vs. 3.11 ± 0.42 mm; P = 0.041). Brachial FMD was similar in pre- and post-PHV youths (P = 0.298), and males and females (P = 0.946). However, exercise-trained youths demonstrated higher FMD when compared with untrained counterparts (5.3 ± 3.3 vs. 3.0 ± 2.6%; P ≤ 0.001). Furthermore, brachial artery diameter (r2 = 0.142; P = 0.007 vs. r2 = 0.004; P = 0.652) and FMD (r2 = 0.138; P = 0.008 vs. r2 = 0.003; P = 0.706) were positively associated with cardiorespiratory fitness in post-, but not pre-PHV youths, respectively. Collectively, our data indicate that exercise training is associated with brachial artery remodeling and enhanced endothelial function during youth. However, arterial remodeling and endothelium-dependent function are only associated with elevated cardiorespiratory fitness during later stages of adolescence.NEW & NOTEWORTHY We report preliminary evidence of the "youth athlete's artery," characterized by training-related arterial remodeling and elevated endothelium-dependent arterial function in children and adolescents. However, training-related adaptations in brachial artery diameter and flow-mediated dilation (FMD) were associated with cardiorespiratory fitness in adolescents, but not in children. Our findings indicate that endothelium-dependent arterial function is modifiable with chronic exercise training during childhood, but the association between FMD and elevated cardiorespiratory fitness is only apparent during later stages of adolescence.

Vascular adaptation to exercise: a systematic review and audit of female representation.

Biological sex is a salient factor in exercise-induced vascular adaptation. Although a male bias is apparent in the literature, the methodological quality of available studies in females is not yet known. This systematic review with narrative synthesis aimed to assess available evidence of exercise interventions on endothelial function, measured using flow-mediated dilation, in otherwise healthy individuals and athletes. A standardized audit framework was applied to quantify the representation of female participants. Using a tiered grading system, studies that met best-practice recommendations for conducting physiological research in females were identified. A total of 210 studies in 5,997 participants were included, with 18% classified as athletes. The primary exercise mode and duration were aerobic (49%) and acute (61%), respectively. Despite 53% of studies (n = 111) including at least one female, female participants accounted for only 39% of the total study population but 49% of the athlete population. Majority (49%) of studies in females were conducted in premenopausal participants. No studies in naturally menstruating, hormonal contraceptive-users or in participants experiencing menstrual irregularities met all best-practice recommendations. Very few studies (∼5%) achieved best-practice methodological guidelines for studying females and those that did were limited to menopause and pregnant cohorts. In addition to the underrepresentation of female participants in exercise-induced vascular adaptation research, there remains insufficient high-quality evidence with acceptable methodological control of ovarian hormones. To improve the overall methodological quality of evidence, adequate detail regarding menstrual status should be prioritized when including females in vascular and exercise research contexts.

Differences in cardiac adaptation to exercise in male and female athletes assessed by noninvasive techniques: a state-of-the-art review.

Athlete's heart is generally regarded as a physiological adaptation to regular training, with specific morphological and functional alterations in the cardiovascular system. Development of the noninvasive imaging techniques over the past several years enabled better assessment of cardiac remodeling in athletes, which may eventually mimic certain pathological conditions with the potential for sudden cardiac death, or disease progression. The current literature provides a compelling overview of the available methods that target the interrelation of prolonged exercise with cardiac structure and function. However, this data stems from scientific studies that included mostly male athletes. Despite the growing participation of females in competitive sport meetings, little is known about the long-term cardiac effects of repetitive training in this population. There are several factors-biochemical, physiological and psychological, that determine sex-dependent cardiac response. Herein, the aim of this review was to compare cardiac adaptation to endurance exercise in male and female athletes with the use of electrocardiographic, echocardiographic, and biochemical examination, to determine the sex-specific phenotypes, and to improve the healthcare providers' awareness of cardiac remodeling in athletes. Finally, we discuss the possible exercise-induced alternations that should arouse suspicion of pathology and be further evaluated.

Characteristics of bone mineral density in patients with functional hypothalamic amenorrhoea and its association with reproductive hormones and body composition.

OBJECTIVE: Bone mineral density (BMD) is typically reduced in patients with female athlete triad (FAT) and anorexia nervosa (AN). However, bone health in most patients with functional hypothalamic amenorrhoea (FHA), who may not suffer from severe energy deficiency, has not received adequate attention in clinical practice. This study aimed to investigate BMD and its association with clinical and endocrine features in individuals with FHA and to provide clinical evidence for improving bone loss and preventing osteoporosis in FHA. DESIGN: To assess the bone status of patients with FHA and investigate its association with various clinical and endocrinological characteristics. PATIENTS: We retrospectively analysed 80 patients with FHA who attended the Obstetrics and Gynecology Hospital of Fudan University from January 2022 to March 2023. MEASUREMENTS: The levels of reproductive hormones, including luteinising hormone (LH), follicle-stimulating hormone, oestradiol (E2 ) and total testosterone (TT), were examined at the time of initial diagnosis, and a body composition analyser was used to measure body fat percentage (BF%), lean body mass (LBM) and segmental muscle/fat. Dual-emission X-ray absorptiometry was used to measure lumbar spine BMD and femoral neck BMD in patients with FHA, and the Z score was calculated. RESULTS: The study cohort consisted of 80 female patients with FHA. The average age of the patients was 24.64 ± 6.02 years, and their body mass index (BMI) was 19.47 ± 2.86 kg/m2 . The duration of weight loss was 12 (6, 24) months, while the duration of oligo/amenorrhoea was 12 (4.5, 24) months. The mean degree of weight loss was 18.39 ± 9.53%. Low BMD were present in 15% of patients with FHA at the lumbar spine and/or femoral neck; 12.5% and 10% had low bone mass at the lumbar spine and femoral neck, respectively. The low bone mass group experienced a longer period of weight loss than the normal group [24 (16.5, 60) vs. 12 (4.5, 24) months, p = .037]. In addition, the abnormal group had a lower BMR (basal metabolic rate, BMR) [1158 ± 85 vs. 1231 ± 91 kcal/day, p = .011] and lower bone mineral content [2.15 ± 0.26 vs. 2.43 ± 0.31 kg, p = .009] than the normal group. Both LBMD and femoral neck BMD (Fn BMD) were positively correlated with BMI, BF%, LBM, and regional muscle/fat mass (all p < .05). There was also a positive correlation between LBMD and basal LH levels (p = .009) and waist-to-hip ratio (p = .034), whereas Fn BMD was positively correlated with TT levels (p = .029). Multiple linear regression analysis showed that LBM was positively associated with LBMD (ß = .007, 95% confidence interval [CI] = 0.004-0.009, p < .001), while trunk muscle mass was positively associated with Fn BMD (ß = .046, 95% CI = 0.013-0.080, p = .008). CONCLUSION: Fifteen percent of the patients with FHA exhibited low bone mass, a condition associated with prolonged weight loss. The basal LH and TT levels showed positive correlations with LBMD and Fn BMD, respectively. Meanwhile, BMR levels, BMI, BF%, and muscle mass were all positively correlated with LBMD and Fn BMD. Clinically, we should be attentive to suboptimal bone health in patients with FHA and take early screening, diagnosis and intervention measures, especially appropriate muscle mass gain, to prevent the onset of osteoporosis and fragility fractures in the long term.

Association analysis of indel variants and gene expression identifies MDM4 as a novel locus for skeletal muscle hypertrophy and power athlete status.

Insertions and deletions (indels) are the second most common type of variation in the human genome. However, limited data on their associations with exercise-related phenotypes have been documented. The aim of the present study was to examine the association between 18,370 indel variants and power athlete status, followed by additional studies in 357,246 individuals. In the discovery phase, the D allele of the MDM4 gene rs35493922 I/D polymorphism was over-represented in power athletes compared with control subjects (P = 7.8 × 10-9) and endurance athletes (P = 0.0012). These findings were replicated in independent cohorts, showing a higher D allele frequency in power athletes compared with control subjects (P = 0.016) and endurance athletes (P = 0.031). Furthermore, the D allele was positively associated (P = 0.0013) with greater fat-free mass in the UK Biobank. MDM4 encodes a protein that inhibits the activity of p53, which induces muscle fibre atrophy. Accordingly, we found that MDM4 expression was significantly higher in the vastus lateralis of power athletes compared with endurance athletes (P = 0.0009) and was positively correlated with the percentage of fast-twitch muscle fibres (P = 0.0062) and the relative area occupied by fast-twitch muscle fibres (P = 0.0086). The association between MDM4 gene expression and an increased proportion of fast-twitch muscle fibres was confirmed in two additional cohorts. Finally, we found that the MDM4 DD genotype was associated with increased MDM4 gene expression in vastus lateralis and greater cross-sectional area of fast-twitch muscle fibres. In conclusion, MDM4 is suggested to be a potential regulator of muscle fibre specification and size, with its indel variant being associated with power athlete status. HIGHLIGHTS: What is the central question of this study? Which indel variants are functional and associated with sport- and exercise-related traits? What is the main finding and its importance? Out of 18,370 tested indels, the MDM4 gene rs35493922 I/D polymorphism was found to be the functional variant (affecting gene expression) and the most significant, with the deletion allele showing associations with power athlete status, fat-free mass and cross-sectional area of fast-twitch muscle fibres. Furthermore, the expression of MDM4 was positively correlated with the percentage of fast-twitch muscle fibres and the relative area occupied by fast-twitch muscle fibres.

Sprint interval training in the postpartum period maintains the enhanced cardiac output of pregnancy: A case study.

During pregnancy an increased cardiac output ( Q ̇ $\dot{Q}$ ) and blood volume (BV) occur to support fetal growth. Increased Q ̇ $\dot{Q}$ and BV also occur during chronic endurance exercise training and benefit performance. We investigated if sprint interval training (SIT) undertaken early postpartum maintains the elevated Q ̇ $\dot{Q}$ and BV of pregnancy and benefits performance. The participant, a competitive field hockey player and former cyclist, visited our laboratory at 2 weeks of gestation (baseline) and postpartum pre-, mid- and post-intervention (PPpre, PPmid and PPpost). Delivery was uncomplicated and she felt ready to start the SIT programme 5 weeks postpartum. Inert gas rebreathing was used to measure peak exercise Q ̇ $\dot{Q}$ ( Q ̇ $\dot{Q}$ peak); V ̇ O 2 peak ${{\dot{V}}_{{{{\mathrm{O}}}_{\mathrm{2}}}{\mathrm{peak}}}}$ was measured with a metabolic cart; and postpartum haematological values were measured with carbon monoxide rebreathing. The 18 SIT sessions progressed from four to eight sprints at 130% of V ̇ O 2 peak ${{\dot{V}}_{{{{\mathrm{O}}}_{\mathrm{2}}}{\mathrm{peak}}}}$ peak power output. Q ̇ $\dot{Q}$ peak increased from baseline at all postpartum time points (baseline 16.2 vs. 17.5, 16.8 and 17.2 L/min at PPpre, PPmid and PPpost, respectively). Relative V ̇ O 2 peak ${{\dot{V}}_{{{{\mathrm{O}}}_{\mathrm{2}}}{\mathrm{peak}}}}$ remained below baseline values at all postpartum measurements (baseline 44.9 vs. 41.0, 42.3 and 42.5 mL/kg/min at PPpre, PPmid and PPpost, respectively) whereas absolute V ̇ O 2 peak ${{\dot{V}}_{{{{\mathrm{O}}}_{\mathrm{2}}}{\mathrm{peak}}}}$ rapidly reached baseline values postpartum (baseline 3.19 vs. 3.12, 3.23 and 3.18 L/min at PPpre, PPmid and PPpost, respectively). Postpartum BV (5257, 4271 and 5214 mL at PPpre, PPmid and PPpost, respectively) and Hbmass (654, 525 and 641 g at PPpre, PPmid and PPpost, respectively) were similar between PPpre and PPpost but decreased alongside Q ̇ $\dot{Q}$ peak at PPmid. Peak power was returned to pre-pregnancy values by intervention end (302 vs. 303 W, baseline vs. PPpost). These findings show that SIT undertaken early postpartum defends the elevated Q ̇ $\dot{Q}$ peak of pregnancy and rapidly returns absolute V ̇ O 2 peak ${{\dot{V}}_{{{{\mathrm{O}}}_{\mathrm{2}}}{\mathrm{peak}}}}$ and peak power to baseline levels. HIGHLIGHTS: What is the central question of this study? Can the enhanced cardiac output of pregnancy be maintained with strenous exercise training undertaken early postpartum. What is the main finding and its importance? Baseline values of absolute oxygen consumption, peak power output and peak exercise cardiac output can be regained rapidly or surpassed following 6 weeks of sprint interval training postpartum. Sprint interval training can be used by endurance trained females to safely resume training early postpartum, allowing a rapid and efficient return to baseline fitness levels.

The Psychology of Athletic Endeavor.

A considerable amount of human behavior occurs within the context of sports. In recent years there have been notable advances in psychological science research applied to understanding athletic endeavor. This work has utilized a number of novel theoretical, methodological, and data analytic approaches. We review the current evidence related to developmental considerations, intrapersonal athlete factors, group processes, and the role of the coach in explaining how athletes function within the sport domain. This body of work sheds light on the diverse ways in which psychological processes contribute to athletic strivings. It also has the potential to spark interest in domains of psychology concerned with achievement as well as to encourage cross-domain fertilization of ideas.

Industrial athletes, relative energy deficit in occupation, and equitable eating disorder treatment and recovery.

OBJECTIVE: This paper highlights the gap in understanding and meeting the needs of individuals with eating disorders (EDs) who are engaged in manual labor and proposes a novel solution for meeting those needs. METHODS: In this paper, we describe the rationale, considerations, and opportunities for research and practice that can be adapted and created to meet the needs of individuals with EDs who are engaged in manual labor, a group that may be underserved by current methods for treating EDs. We highlight the potential utility of the industrial athlete (IA) framework for this population, propose the term Relative Energy Deficit in Occupation ("RED-O"), and describe the potential applications of this framework and term for research, treatment, and public health promotion for EDs among individuals engaged in manual labor. RESULTS: The IA framework and RED-O provide opportunities to address the unique needs of individuals with EDs who are also engaged in manual labor and who are disproportionately of low socioeconomic status through new and adapted research and clinical applications as well as advocacy and public health promotion. DISCUSSION: Equitable recovery for people with EDs requires the ability to engage in activities necessary for occupational functioning, including the physical capacity necessary to participate fully in their work. As access to treatment increases, it is imperative that the needs of IAs are adequately addressed, especially those who are of lower socioeconomic status. PUBLIC SIGNIFICANCE: The industrial athlete and relative energy deficit in occupation (RED-O) frameworks will enhance opportunities for identification and treatment of underserved and disadvantaged populations with eating disorders and reduce public health burden of eating disorders.

Pelvic Floor Muscle Training on Stress Urinary Incontinence in Power- and Weightlifters: a Pilot Study.

INTRODUCTION AND HYPOTHESIS: Stress urinary incontinence (SUI) is defined as involuntary leakage of urine on physical effort and is prevalent among power- and weightlifters. However, there is scant knowledge on treatment options for this population. The aim of this pilot study was to evaluate the potential outcomes and feasibility of a pelvic floor muscle training (PFMT) program on SUI in nulliparous female power- and weightlifters. METHODS: This was a case-series study, including one weightlifter and two powerlifters aged 21-32 years. The participants conducted 12 weeks of PFMT at home, with weekly follow-up by a physiotherapist. Change in total score of the International Consensus of Incontinence Questionnaire Urinary Incontinence Short Form (ICIQ-UI-SF) was the primary outcome. Secondary outcome was perceived change assessed by the Patient Global Impression of Improvement (PGI-I) Scale and impact on sport participation. PFM strength, endurance, and resting pressure was measured using vaginal manometry. Feasibility was evaluated as adherence to training and self-efficacy (Self Efficacy Scale for Practicing Pelvic Floor Exercises). RESULTS: One athlete reduced their ICIQ-UI-SF score and experienced improvement in symptoms. One athlete reported no change, and one reported a worsening of symptoms. All three participants improved PFM strength and endurance, completed the testing, and 12 weeks of PFMT, but adherence varied between 40 and 80%. Participants reported a lack of time and energy and forgetting to perform the exercises, as reasons for low adherence. CONCLUSION: There were varying effects of a 12-week PFMT program on SUI in three strength athletes. The results can create the basis for a future randomized controlled trial.

What makes an athlete? A scoping review: Assessing the use of the word athlete with anterior cruciate ligament rehabilitation review studies. Is there a standard?

The term athlete does not currently have an agreed definition or standardized use across the literature. We analyzed the use of the term "athlete" amongst review studies specific to Anterior Cruciate Ligament (ACL) rehabilitation to investigate if the term was justified in its use. A comprehensive review of a database was performed to identify review papers which used the term "athlete" in the title, and which were related to ACL rehabilitation and surveillance. These papers were analyzed and their source papers were extracted for review. Twenty-eight review papers were identified. Source studies were extracted and analyzed. After removal of duplicates 223 source papers were identified. Despite using the term "athlete" in the review study titles only 5/17 (10.7%) sufficiently justified the use of this term. The term athlete was used in 117/223 (52.5%) of the source studies. Of those, 78/117 source studies (66.7%) justified the term athlete. The remaining 39/117 (33.3%) papers where participants were stated to be athletes, gave no justification. The ambiguous use of the term athlete amongst published studies highlights the need for a definition or justification of the term to be used in studies. The lack of a standard definition leads to the potential for studies to dilute high quality data by the potentially differing rehabilitation requirements and access to resources available to those with varying exercise levels. The indiscriminate use of the term athlete could lead to participants with widely ranging physical activity levels being included in the same study, and being used to create clinical advice for all. Advice could potentially vary across those of differing physical activity levels.

Early morning sport scheduling is associated with poorer subjective sleep characteristics in British student-athletes.

This study presents the sleep characteristics of British student-athletes and examines the relationships between sport scheduling and time demands on sleep outcomes. Student-athletes (n = 157, 51% male) completed the Pittsburgh Sleep Quality Index (PSQI), Epworth Sleepiness Scale (ESS), and the Sleep Hygiene Index (SHI). Self-reported sleep characteristics on weekdays and weekends, weekly frequencies of early morning and late evening sport sessions, and academic-related and sport-related time demands were also collected. Questionnaires revealed a high prevalence of undesired sleep characteristics including poor sleep quality (global PSQI >5 in 49.0%) and low sleep durations on weekdays (25% reporting <7 h). Paired t-tests revealed significant differences in bedtime, waketime, sleep duration, and sleep onset latency between weekdays and weekends (all p < 0.01). Hierarchical regression analyses indicated that early morning sport frequency was a significant predictor of PSQI (ß = 0.30) and SHI (ß = 0.24) global scores, weekday waketimes (ß = -0.17), and weekday sleep durations (ß = -0.25; all p < 0.05) in models adjusted for participant characteristics. Late evening sport frequency, and academic-related and sport-related time demands, were not significant predictors of any sleep outcome. Adjusting sport scheduling to avoid early start times could provide a means to improve sleep outcomes and may improve sporting performance and academic attainment.

Food for thought: Physiological considerations for nutritional ergogenic efficacy.

Top-class athletes have optimized their athletic performance largely through adequate training, nutrition, recovery, and sleep. A key component of sports nutrition is the utilization of nutritional ergogenic aids, which may provide a small but significant increase in athletic performance. Over the last decade, there has been an exponential increase in the consumption of nutritional ergogenic aids, where over 80% of young athletes report using at least one nutritional ergogenic aid for training and/or competition. Accordingly, due to their extensive use, there is a growing need for strong scientific investigations validating or invalidating the efficacy of novel nutritional ergogenic aids. Notably, an overview of the physiological considerations that play key roles in determining ergogenic efficacy is currently lacking. Therefore, in this brief review, we discuss important physiological considerations that contribute to ergogenic efficacy for nutritional ergogenic aids that are orally ingested including (1) the impact of first pass metabolism, (2) rises in systemic concentrations, and (3) interactions with the target tissue. In addition, we explore mouth rinsing as an alternate route of ergogenic efficacy that bypasses the physiological hurdles of first pass metabolism via direct stimulation of the central nervous system. Moreover, we provide real-world examples and discuss several practical factors that can alter the efficacy of nutritional ergogenic aids including human variability, dosing protocols, training status, sex differences, and the placebo effect. Taking these physiological considerations into account will strengthen the quality and impact of the literature regarding the efficacy of potential ergogenic aids for top-class athletes.

Jumping demands during classical ballet class.

Ballet class represents a considerable portion of professional ballet training, yet the external training load demands associated with class-and particularly the jumping demands-have not been investigated. The purpose of this study was to measure the jumping demands of ballet class by sex and rank. Eleven female and eight male elite professional ballet dancers participated in 109 ballet classes taught by 12 different teachers. Jump counts and jump heights were measured during each class. A Poisson generalized linear mixed effects model was used to examine the differences in jump counts between sexes and ranks. Greater jump counts were observed during class in men than in women (153, 95% confidence intervals [CI] [137, 170] vs. 119, 95% CI [109, 131], p = 0.004) and in junior ranking dancers compared with senior ranking dancers (151, 95% CI [138, 165] vs. 121, 95% CI [108, 135], p = 0.006). Female junior and senior ranking dancers jumped at rates of 9.2 ± 2.6 and 8.6 ± 4.7 jumps·min-1 , respectively, while male junior and senior ranking dancers jumped at rates of 9.1 ± 2.6 and 8.7 ± 2.6 jumps·min-1 , respectively. Across all classes, 73% of jumps observed were below 50% of maximum double-legged countermovement jump height. Unlike rehearsals and performances, class offers dancers an opportunity to self-regulate load, and as such, are a useful session to manage jump load, and facilitate gradual return-to-dance pathways. Communication between health care and artistic staff is essential to facilitate load management during class.

Slackline training for Paralympic alpine sit skiers: Development of human-device multi-joint coordination.

PURPOSE: Para-alpine sit skiers face unique challenges in balance control due to their disabilities and the use of sit skis. This study assessed their multi-joint coordination before and after slackline training. METHODS: Nine alpine sit skiers (6 M/3 F; 27 ± 8 years; height: 168.3 ± 6.0 cm; body mass: 55.4 ± 6.9 kg) with different disabilities (LW10-LW12) volunteered for the experiment. All subjects performed slackline training for 5 weeks (20 sessions). Joint kinematics were captured by vision-based markerless motion analysis. Root mean square (RMS) amplitude, mean velocity and mean power frequency (MPF) were evaluated. RESULTS: After training, performance improved significantly with an increase in balance time (1041%, p = 0.002), and a decrease in joint angular velocities and RMS amplitude of the sit ski foot (p < 0.05). Joint synergies were developed through in- or anti-phase movements between joint pairs, particularly involving the hip joints (continuous relative phase angles ~0° or 180°, p < 0.001). Multi-joint coordination shifted from large-RMS amplitude of elbows to low-MPF large-RMS amplitude of the hip and shoulders (p < 0.05), with a significant increase of hip weighting (77.61%, p = 0.031) in the principal component analysis. The coordination was maintained with the change of slackline tension (p < 0.05). Athletes with severe trunk disabilities (LW10) had shorter balance time and poorer coordination than athletes with full trunk functions (LW12). CONCLUSIONS: Our findings showed the development of joint coordination involving better control of the hip and sit skis during the challenging slackline training task.

Global practitioner assessment and management of mental fatigue and mental recovery in high-performance sport: A need for evidence-based best-practice guidelines.

BACKGROUND: Mental fatigue and mental recovery have gained scientific attention in relation to sporting performance, yet best practice assessment and management methods are lacking. A greater understanding of current knowledge and practices in high-performance sport are necessary. OBJECTIVE: To understand the contemporary knowledge, beliefs, monitoring processes, management strategies, perceived responsibility, sources of evidence, and challenges, when assessing the mental fatigue and mental recovery of athletes in high-performance sport. METHODS: A mixed-methods survey approach obtained information from 156 multi-disciplinary high-performance sport practitioners. Descriptive outputs were reported and potential differences between key concepts were detected using Wilcoxon-signed rank analysis. Thematic analysis interpreted open-text responses. RESULTS: Only 11.5% and 5.1% of respondents indicated they were "very" knowledgeable about mental fatigue and mental recovery, respectively. Knowledge (p < 0.001) and confidence in application (p = 0.001) were significantly greater for mental fatigue than mental recovery. Nearly all respondents perceived mental fatigue and mental recovery impacted training and competition performance, with a greater negative impact during competition (p < 0.001). A limited number of respondents reported deliberate assessment (31.1%) or management (51.2%) of mental fatigue and mental recovery. A combination of sources of evidence were used to inform practice, with common challenges to implementation including staff knowledge, athlete-buy in, time-availability, and a lack of evidence. Practitioners reported that assessing and managing mental fatigue and mental recovery was multi-disciplinary in nature. CONCLUSION: Practitioners reported that mental fatigue and mental recovery did impact performance, yet this was not reflected in the implementation of evidence-based assessment and management practices in high-performance sport.

Head Acceleration Events During Tackle, Ball-Carry, and Ruck Events in Professional Southern Hemisphere Men's Rugby Union Matches: A Study Using Instrumented Mouthguards.

OBJECTIVES: Describe head acceleration events (HAEs) experienced by professional male rugby union players during tackle, ball-carry, and ruck events using instrumented mouthguards (iMGs). DESIGN: Prospective observational cohort. METHODS: Players competing in the 2023 Currie Cup (141 players) and Super Rugby (66 players) seasons wore iMGs. The iMG-recorded peak linear acceleration (PLA) and peak angular acceleration (PAA) were used as in vivo HAE approximations and linked to contact-event data captured using video analysis. Using the maximum PLA and PAA per contact event (HAEmax), ordinal mixed-effects regression models estimated the probabilities of HAEmax magnitude ranges occurring, while accounting for the multilevel data structure. RESULTS: As HAEmax magnitude increased the probability of occurrence decreased. The probability of a HAEmax ≥15g was 0.461 (0.435-0.488) (approximately 1 in every 2) and ≥45g was 0.031 (0.025-0.037) (1 in every 32) during ball carries. The probability of a HAEmax >15g was 0.381 (0.360-0.404) (1 in every 3) and >45g 0.019 (0.015-0.023) (1 in every 53) during tackles. The probability of higher magnitude HAEmax occurring was greatest during ball carries, followed by tackles, defensive rucks and attacking rucks, with some ruck types having similar profiles to tackles and ball carries. No clear differences between positions were observed. CONCLUSION: Higher magnitude HAEmax were relatively infrequent in professional men's rugby union players. Contact events appear different, but no differences were found between positions. The occurrence of HAEmax was associated with roles players performed within contact events, not their actual playing position. Defending rucks may warrant greater consideration in injury prevention research.

Menstrual cycle characteristics, perceived impact on performance, and barriers to communication: Perspectives of high-performance adolescent athletes in Singapore.

The purpose of this study was to examine the menstrual cycle (MC) characteristics, explore the impact on performance, and identify barriers to and facilitators of MC-related communication among high-performance female adolescent athletes in Singapore. Ninety athletes (15.4 ± 1.8 years) from multiple sports completed an online questionnaire. Eighty-four athletes were postmenarcheal (menarcheal age 11.9 ± 1.3 years), including two who were using an oral contraceptive pill (OCP). Secondary amenorrhea, current or history of, was self-reported in 16% of athletes. Sixty-two percent and 67% of non-OCP athletes perceived that the MC affected their ability to train and compete, respectively. Athletes preferred speaking to a parent (85%) and a female figure (67%) about MC-related concerns. Through thematic analysis, three barriers to communication were constructed: (1) pervasive menstrual stigma, (2) constraints of the training environment, and (3) the low value placed on MC-related conversations. Two facilitators of communication were constructed: (1) respect athletes' individual experiences as menstruating girls and (2) foster a safe space for MC-related conversations. Findings demonstrated that menstrual irregularities are common in adolescent athletes and screening for MC disorders, particularly primary amenorrhea should be undertaken in this population, with clear support pathways for management including symptom mitigation. To support athletes in raising MC-related concerns when needed, structured communication pathways that consider individual preferences and involve a (female) point of contact should be established within the training environment. Improving menstrual health literacy among adolescent athletes before any misinformation or negative perceptions are firmly established may contribute to longevity in their athletic careers.

Lack of cardiac remodelling in elite endurance athletes: an unexpected and not so rare finding.

PURPOSE: Endurance elite athletes are expected to present a cardiac remodelling, characterized by eccentric hypertrophy (EH), may be associated with higher sportive performances. However, not all can present a cardiac remodelling. The study aimed to identify endurance athletes without cardiac remodelling characterizing their physiologic and clinical features. METHODS: We studied 309 endurance athletes (cycling, rowing, canoeing, triathlon, athletics, long-distance swimming, cross-country skiing, mid-long distance track, pentathlon, biathlon, long-distance skating and Nordic-combined) examined during period of training, by clinical evaluation, ECG, echocardiogram and exercise-stress test. Sport career achievements (Olympic\World championship medals or national\world records) were recorded. RESULTS: EH was found in most of athletes, (n = 126, 67% of males; n = 85, 68.5% of females). A significant proportion,, exhibited normal geometry (NG) ( n = 59, 31.3% in males; n = 39, 31.4% in females). At stress test, significant differences between EH and NG athletes were found in peak power (317.1 ± 71.2W in NG vs. 342.2 ± 60.6W in EH, p = 0.014 in males and 225.1 ± 38.7W in NG vs. 247.1 ± 37W in EH, p = 0.003 in females), rest heart rate (66.1 ± 13 in NG vs. 58.6 ± 11.6 in EH, p = 0.001 in males and 68 ± 13.2 in NG vs. 59.2 ± 11.2 in EH, p = 0.001 in females) with similar ventricular extrasystoles (p = 0.363 in males and p = 0.492 in females). However, no significant differences in athletic achievements were registered. CONCLUSION: Our study demonstrates a relatively high prevalence of NG in endurance athletes, in addition to the expected EH. Athletes with NG perform worse in exercise-stress test and exhibit some less advantageous functional heart characteristics. However, the type of heart geometry is not associated with negative clinical findings.