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One of the biggest challenges facing numerous young athletes is attempting to perform safely and effectively in the heat. An even greater performance challenge and risk for incurring exertional heat injury is encountered when a young athlete has to compete multiple times on the same day, with only a short rest period between rounds of play, during a hot-weather tournament. Within the scope of the rules, tournament directors frequently provide athletes with only the minimum allowable time between same-day matches or games. Notably, prior same-day exercise has been shown to increase cardiovascular and thermal strain and perception of effort in subsequent activity bouts, and the extent of earlier exercise-heat exposure can affect performance and competition outcome. Incurred water and other nutrient deficits are often too great to offset during short recovery periods between competition bouts, and the athletes are sometimes 'forced' to compete again not sufficiently replenished. Providing longer rest periods between matches and games can significantly improve athlete safety and performance, by enhancing recovery and minimizing the 'carryover' effects from previous competition-related physical activity and heat exposure that can negatively affect performance and safety. Governing bodies of youth sports need to address this issue and provide more specific, appropriate and evidence-based guidelines for minimum rest periods between same-day contests for all levels of tournament play in the heat. Youth athletes are capable of tolerating the heat and performing reasonably well and safely in a range of hot environments if they prepare well, manage hydration sufficiently, and are provided the opportunity to recover adequately between contests. [ABSTRACT FROM AUTHOR]

Objective: To examine on-court core body temperature (T(C)) and sweat loss, as well as pre- and post-play hydration status, in elite adolescent tennis players during a national championships event in a hot climate.Methods: Eight healthy, fit, young male tennis players (mean (SD) age 13.9 (0.9) years; mass 56.0 (10.7) kg; height 169.2 (14.7) cm) were evaluated during first-round singles competition at the National Boys' 14s Junior Championships in the heat (wet-bulb globe temperature (WBGT) 29.6 (0.4) degrees C). Five of those same players were also evaluated during a same-day doubles match (WBGT 31.3 (0.5) degrees C).Results: During doubles (4.37 (0.35) h after singles), pre-play urine specific gravity (USG) (1.025 (0.002); p = 0.06) and total sweat loss (1.9 (0.2) litres; p = 0.10) tended to be higher before and during doubles, respectively, compared to singles. However, percentage change in body mass (-0.5 (0.3) %) tended to be comparatively less (p = 0.08), even though the doubles matches were generally longer (106.6 (11.2) vs 78.8 (10.9) min; p = 0.09) and the degree minutes total was greater (p = 0.04). T(C) increased (p<0.001) during singles and remained elevated, even after 10 min following the end of play. Notably, pre-play (singles) USG was strongly associated (p = 0.005) with the players' final T(C) (38.7 (0.3) degrees C) recorded at the end of singles play.Conclusion: Junior tennis players who begin a match not well hydrated could have progressively increasing thermal strain and a greater risk for exertional heat illness as the match advances. [ABSTRACT FROM AUTHOR]

OBJECTIVE: To survey high school American football programs regarding current prevention measures for reducing heat injuries during the football season. DESIGN: Web-based survey of 27 questions based on consensus statement guidelines by the American College of Sports Medicine on reducing heat injury risk in youth football. SETTING: National (United States) and community-based. PARTICIPANTS: High school programs receiving survey distribution from their state athletic association and the National Federation of State High School Associations. MAIN OUTCOME MEASURES: Responses (percentage and incidence) to questions on preseason acclimatization procedures, practice modification protocols, preparticipation risk factors, hydration management strategies, rest period strategies, heat injury education and policies, and preparation for heat-related emergency care. RESULTS: A total of 540 high school football programs from 26 states completed the survey. The reported number of preseason heat injuries per program (1.38+/-2.08) was greater (P<0.001) compared to during the regular season (0.98+/-1.84). Programs modified equipment configurations during preseason (no helmets or pads, 31.3%; just helmets, 57.0%; helmets and shoulder pads only, 33.5%) or altered the practice schedule when there was excessive heat. Hydration management, education, and preparation for dealing with an acute heat injury varied among programs. CONCLUSIONS: Greater implementation of effective prevention measures to reduce the incidence of heat-related injury and death in high school American football is needed. Strategies should focus on modifying practices appropriately on a day-to-day basis to minimize heat strain and optimize hydration, identifying and educating at-risk individuals during the preparticipation period, and developing an emergency action plan for effectively managing heat injuries. [ABSTRACT FROM AUTHOR]

OBJECTIVE: To examine effects of exercise in the heat and fluid intake on erythrocyte sickling and neutrophil activation in carriers of sickle cell trait (HbAS). DESIGN, SETTING, AND PARTICIPANTS: Six African American men (2 HbAS; 42% HbS, 4 HbAA; 20.7 +/- 0.8 years; 87.4 +/- 9.6 kg) participated in 2 randomized sessions (separate days) each consisting of 45 minutes of brisk walking (treadmill) in a hot (33 degrees C) environment. INTERVENTION: Subjects consumed no fluids or fluid for 3 hours prior to (ad libitum) and during (1.02 L) testing. MAIN OUTCOME MEASUREMENTS: Core temperature, heart rate, and perceived exertion were measured. Forearm venous blood was analyzed for percent erythrocyte sickling and plasma myeloperoxidase. RESULTS: Time-averaged heart rate (126.6 +/- 5.7 vs. 146.7 +/- 5.9 bpm; P = 0.02) and core temperature (37.6 +/- 0.1 vs. 38.1 +/- 0.1 degrees C; P < 0.05) responses were lower during fluid versus no fluid, with no statistically significant difference in perceived exertion (12.3 +/- 0.5 vs. 13.6 +/- 0.4; P = 0.06). Erythrocyte sickling progressively increased (to 3.5%-5.5%) for HbAS carriers during no fluid exercise only. No sickling was detected in HbAA subjects. Plasma myeloperoxidase responses to exercise were greater (P = 0.03) in HbAS versus HbAA. CONCLUSIONS: Fluid ingestion at a rate sufficient to offset a body weight deficit can effectively reduce erythrocyte sickling during exercise in the heat. [ABSTRACT FROM AUTHOR]

Objective: To describe the evidence pertaining to associations between growth, maturation and injury in elite youth athletes., Design: Scoping review., Data Sources: Electronic databases (SPORTDiscus, Embase, PubMed, MEDLINE and Web of Science) searched on 30 May 2023., Eligibility Criteria: Original studies published since 2000 using quantitative or qualitative designs investigating associations between growth, maturation and injury in elite youth athletes., Results: From an initial 518 titles, 36 full-text articles were evaluated, of which 30 were eligible for final inclusion. Most studies were quantitative and employed prospective designs. Significant heterogeneity was evident across samples and in the operationalisation and measurement of growth, maturation and injury. Injury incidence and burden generally increased with maturity status, although growth-related injuries peaked during the adolescent growth spurt. More rapid growth in stature and of the lower limbs was associated with greater injury incidence and burden. While maturity timing did not show a clear or consistent association with injury, it may contribute to risk and burden due to variations in maturity status., Conclusion: Evidence suggests that the processes of growth and maturation contribute to injury risk and burden in elite youth athletes, although the nature of the association varies with injury type. More research investigating the main and interactive effects on growth and maturation on injury is warranted, especially in female athletes and across a greater diversity of sports., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

With the pronounced ongoing growth of global youth sports, opportunities for and participation of youth athletes on the world sports stage, including the Olympic Games, are expected to escalate. Yet, adolescence is a vulnerable period of development and inherently dynamic, with non-linear and asynchronous progression of physical, physiological, psychological and social attributes. These non-concurrent changes within and between individuals are accompanied by irregular and unpredictable threats and impediments. Likewise, the evident age-based criteria and conventional path for those youth athletes deemed eligible candidates for the Olympic Games are not well or consistently defined. Furthermore, the unstructured and largely varying policies and practices across the sporting International Federations specific to youth participation underscore the need to establish a contemporary universal paradigm that would enable elite youth athletes to navigate an individualised healthy pathway to personal, athletic and sport success. First, we reviewed and summarised key challenges facing elite youth athletes and the relevant evidence fundamental to facilitating and supporting central aspects of health and well-being, while empowering safe, sustainable and positive engagement during athletic and personal advancement and competition. Second, we developed and present a modern elite youth athlete model that emphasises a child-centred, practical framework with corresponding guidelines and recommendations to protect health and well-being while safely and favourably managing international sport competition. Our proposed evidence-informed paradigm will enable and support individualised pathways for healthy, well-rounded and sustainable positive engagement while achieving sport success for youth contending or aiming to compete at world-class international sporting events., Competing Interests: Competing interests: MM is a Deputy Editor of the British Journal of Sports Medicine and a member of the Editorial Board of the Injury Prevention and Health Promotion editions., (© Author(s) (or their employer(s)) 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: There is increasing recognition of the prevalence and risk factors for mental health symptoms and disorders among adult elite athletes, with less research involving elite youth athletes. This scoping review aimed to characterise the mental health and well-being of elite youth athletes who travel internationally and compete for their sport., Method: Four databases were searched in March 2023. Inclusion criteria were studies with elite youth athlete populations (mean age 12-17 years) reporting mental health and well-being outcomes. Data from included studies were charted by outcome, and risk/protective factors identified., Results: Searches retrieved 3088 records, of which 33 studies met inclusion criteria, encapsulating data from 5826 athletes (2538 males, 3288 females). The most frequently studied issue was disordered eating (k=16), followed by anxiety (k=7), depression (k=5) and mixed anxiety/depression (k=2). Caseness estimates (a symptom level where mental health treatment is typically indicated) for disordered eating were wide ranging (0%-14% for males; 11%-41% for females), whereas only two studies estimated caseness for depression (7% in a mixed-sex sample; 14% for males, 40% for females) and one for anxiety (8% for males, 28% for females). Common risk factors for mental ill-health included sex, athlete status (compared with non-athletes) and social/relationship factors (with coaches/parents/peers). Contradictory evidence was observed for elite/competition level, which was associated with higher and lower rates of disordered eating., Conclusion: Further representative research into the mental health and well-being of elite youth athletes is needed to enhance understanding and guide prevention and intervention measures., Competing Interests: Competing interests: MM is the deputy editor of the BJSM and a member of the editorial board for the BJSM Injury Prevention & Health Promotion Journal., (© Author(s) (or their employer(s)) 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

Objective: The objective of this study is to characterise the key factors that influence positive engagement and desirable developmental outcomes in sport among elite youth athletes by summarising the methods, groups and pertinent topical areas examined in the extant published research., Design: Scoping review., Data Sources: We searched the databases SPORTDiscus, APA PsycINFO, Web of Science and Sports Medicine & Education Index for peer-reviewed, published in English articles that considered the factors influencing positive developmental outcomes for athletes under 18 years competing at a national and/or international level., Results: The search returned 549 articles, of which 43 met the inclusion criteria. 16 studies used a qualitative approach, 14 collected quantitative data, 2 adopted mixed methods and 11 were reviews. Seven articles involved athletes competing in absolute skill contexts (ie, against the best athletes of any age) while the majority involved athletes competing in relative skill contexts (ie, against the best in a specific age or developmental group). The studies described the characteristics of the athletes, as well as their training, relationships with others, social and physical environments, and/or their overall developmental pathways., Conclusion: Existing research on positive engagement in elite youth sport aligned with and mapped onto established models of positive development in youth sport more generally. Our findings further support that, while certain youth athletes may demonstrate extraordinary performance capabilities, they are still children who benefit from positive engagement prompted and reinforced by developmentally appropriate and supportive activities, relationships and environments., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

Few previous review articles have focused on the associations between inadequate daily water intake (LOW) or urinary biomarkers of dehydration ( U D; low urine volume or high urine osmolality) and multiple diseases. Accordingly, we conducted manual online searches (47 key words) of the PubMed, Embase, and Google Scholar databases with these inclusion criteria: English language, full-text, peer reviewed, no restriction on research design, and three publications minimum. Initially, 3,903 articles were identified based on their titles and abstracts. Evaluations of full length .pdf versions identified 96 studies that were acceptable for inclusion. We concluded that the evidence is insufficient or conflicting for seven disorders or diseases (i.e. suggesting the need for additional clarifying research) and it is lacking for all-cause mortality. Differential characterizations among women and men have been reported in the results of nine studies involving five diseases. Finally, the evidence for associations of LOW or U D is strong for both kidney stones and type 2 diabetes with hyperglycemia. This suggests that great public health value (i.e. reduced disease risk) may result from increased daily water intake-a simple and cost-effective dietary modification., Competing Interests: Declaration of conflicting interestsThe authors declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: LEA is a Board of Trustees member and occasional consultant for the Drinking Water Research Foundation, Alexandria, VA; MFB – no conflicts of interest; CXM – is an occasional consultant for and has an active research grant with Kraft Heinz Co.; SAK has active research grants during the past 36 months from the National Science Foundation, USDA, Kraft Heinz, Unilever, and Standard Process. During this time, he was a lead research aerospace physiologist at Luke Air Force Base, AZ and served as a member of the science advisory board for Hyduro Inc, Zico Rising, and Rockley Photonics. He has also provided scientific consultation to the American Beverage Association, Unilever, Pepsico, and Kraft Heinz Co.

Introduction: Continuous recognition tasks (CRTs) assess episodic memory (EM), the central functional disturbance in Alzheimer's disease and several related disorders. The online MemTrax computerized CRT provides a platform for screening and assessment that is engaging and can be repeated frequently. MemTrax presents complex visual stimuli, which require complex involvement of the lateral and medial temporal lobes and can be completed in less than 2 min. Results include number of correct recognitions (HITs), recognition failures (MISSes = 1-HITs), correct rejections (CRs), false alarms (FAs = 1-CRs), total correct (TC = HITs + CRs), and response times (RTs) for each HIT and FA. Prior analyses of MemTrax CRT data show no effects of sex but an effect of age on performance. The number of HITs corresponds to faster RT-HITs more closely than TC, and CRs do not relate to RT-HITs. RT-HITs show a typical skewed distribution, and cumulative RT-HITs fit a negative survival curve (RevEx). Thus, this study aimed to define precisely the effects of sex and age on HITS, CRs, RT-HITs, and the dynamics of RTs in an engaged population., Methods: MemTrax CRT online data on 18,255 individuals was analyzed for sex, age, and distributions of HITs, CRs, MISSes, FAs, TC, and relationships to both RT-HITs and RT-FAs., Results: HITs corresponded more closely to RT-HITs than did TC because CRs did not relate to RT-HITs. RT-FAs had a broader distribution than RT-HITs and were faster than RT-HITs in about half of the sample, slower in the other half. Performance metrics for men and women were the same. HITs declined with age as RT-HITs increased. CRs also decreased with age and RT-FAs increased, but with no correlation. The group over aged 50 years had RT-HITs distributions slower than under 50 years. For both age ranges, the RevEx model explained more than 99% of the variance in RT-HITs., Discussion: The dichotomy of HITs and CRs suggests opposing cognitive strategies: (1) less certainty about recognitions, in association with slower RT-HITs and lower HIT percentages suggests recognition difficulty, leading to more MISSes, and (2) decreased CRs (more FAs) but faster RTs to HITs and FAs, suggesting overly quick decisions leading to errors. MemTrax CRT performance provides an indication of EM (HITs and RT-HITs may relate to function of the temporal lobe), executive function (FAs may relate to function of the frontal lobe), processing speed (RTs), cognitive ability, and age-related changes. This CRT provides potential clinical screening utility for early Alzheimer's disease and other conditions affecting EM, other cognitive functions, and more accurate impairment assessment to track changes over time., Competing Interests: CA is the Owner of MemTrax, LLC, which provided the MemTrax online test to the French company, HAPPYneuron, Inc., which administered the test as part of a battery of tests to evaluate and improve cognitive function and was employed by CogniFit, LLC. FT-B was employed by HAPPYneuron, Inc. during the time the data on MemTrax was collected. JA has been an informal adviser to MemTrax, LLC and owns the MemTrax website. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Clifford, Anand, Tarpin-Bernard, Bergeron, Ashford, Bayley and Ashford.)

Purposes: To establish a normative range of MemTrax (MTx) metrics in the Chinese population., Methods: The correct response percentage (MTx-%C) and mean response time (MTx-RT) were obtained and the composite scores (MTx-Cp) calculated. Generalized additive models for location, shape and scale (GAMLSS) were applied to create percentile curves and evaluate goodness of fit, and the speed-accuracy trade-off was investigated., Results: 26,633 subjects, including 13,771 (51.71%) men participated in this study. Age- and education-specific percentiles of the metrics were generated. Q tests and worm plots indicated adequate fit for models of MTx-RT and MTx-Cp. Models of MTx-%C for the low and intermediate education fit acceptably, but not well enough for a high level of education. A significant speed-accuracy trade-off was observed for MTx-%C from 72 to 94., Conclusions: GAMLSS is a reliable method to generate smoothed age- and education-specific percentile curves of MTx metrics, which may be adopted for mass screening and follow-ups addressing Alzheimer's disease or other cognitive diseases., Highlights: GAMLSS was applied to establish nonlinear percentile curves of cognitive decline. Subjects with a high level of education demonstrate a later onset and slower decline of cognition. Speed-accuracy trade-off effects were observed in a subgroup with moderate accuracy. MemTrax can be used as a mass-screen instrument for active cognition health management advice., (© 2023 The Authors. Alzheimer's & Dementia published by Wiley Periodicals LLC on behalf of Alzheimer's Association.)

Background: Whereas the Montreal Cognitive Assessment (MoCA) and Addenbrooke's cognitive examination-revised (ACE-R) are commonly used tests for the detection of post-stroke cognitive impairment (PSCI), these instruments take 10-30 min to administer and do not assess processing speed, which is a critical impairment in PSCI. MemTrax (MTx) is a continuous recognition test, which evaluates complex information processing, accuracy, speed, and attention, in 2 min., Aim: To evaluate whether MTx is an effective and practical tool for PSCI assessment., Methods: This study enrolled acute ischemic stroke (AIS) patients who have assessed the cognitive status including MTx, clinical dementia rating (CDR), MoCA, Neuropsychiatric Inventory (NPI), Hamilton depression scale (HAMD), Hamilton anxiety scale (HAMA), the National Institute of Health Stroke Scale (NIHSS), modified Rankin scale (mRS), and Barthel Index of activity of daily living (BI) combined with the physical examinations of the neurologic system at the 90-day (D90) after the AIS. The primary endpoint of this study was establishing MTx cut-offs for distinguishing PSCI from AIS., Results: Of the 104 participants, 60 were classified to the PSCI group. The optimized cut-off value of MTx-%C (percent correct) was 78%, with a sensitivity and specificity for detecting PSCI from Non-PSCI of 90.0 and 84.1%, respectively, and an AUC of 0.919. Regarding the MTx-Cp (Composite score = MTx-%C/MTx-RT), using 46.3 as a cut-off value, the sensitivity and specificity for detecting PSCI from Non-PSCI were 80.0 and 93.2%, with an AUC of 0.925. Multivariate linear regression showed that PSCI reduced the MTx-%C (Coef. -14.18, 95% CI -18.41∼-9.95, p < 0.001) and prolonged the MTx-RT (response time) (Coef. 0.29, 95% CI 0.16∼0.43, p < 0.001) and reduced the MTx-CP (Coef. -19.11, 95% CI -24.29∼-13.93, p < 0.001)., Conclusion: MemTrax (MTx) is valid and effective for screening for PSCI among target patients and is a potentially valuable and practical tool in the clinical follow-up, monitoring, and case management of PSCI., Competing Interests: JA had filed a patent application for the use of the specific continuous recognition paradigm described in this article for general testing of memory and also owns the URL for www.memtrax.com. XZho is the Executive Director and legal representative of SJN Biomed company. This company is managing the Chinese version of memory testing system described in this article, owns the URL, www.memtrax.com.cn as well as the mini program version of MemTrax on WeChat. XZho was employed by Zhongze Therapeutics. JZ was employed by Bothwin Clinical Study Consultant. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Zhao, Dai, Zhang, Chen, Zhao, Bergeron, Zhou, Zhang, Zhong, Ashford and Liu.)

First morning urine (FMU) assessment would be a practical and convenient solution for clinically acceptable detection of underhydration prior to competition/training, and for the general public. Thus, we thus sought to determine the diagnostic accuracy of FMU as a valid indicator of recent (previous 24 hr, 5 days average) hydration practices. For 5 consecutive days and one final morning, 67 healthy women (n = 38) and men (n = 29; age: 20 [1] years, body mass index: 25.9 [5.5]) completed 24-hr diet logs for total water intake (from beverages and foods, absolute and relative to body mass), 24-hr urine and FMU collection (last morning only) for osmolality (Osm), specific gravity (SG), and color (Col), and morning blood sampling for plasma osmolality and copeptin. Correlations determined significance and relationship strength among FMU and all other variables. Area under the receiver operating characteristic curves, sensitivity, specificity, and positive likelihood ratios were employed using previously reported values to indicate underhydration (total water intake < 30 ml/kg, osmolality > 500, and >800 mOsm/kg, specific gravity > 1.017, and copeptin > 6.93 pmol/L). FMU&#95;Osm and FMU&#95;SG were significantly correlated (p < .05) to all variables except the previous 5-day plasma osmolality. FMU&#95;Col was only significantly correlated with other color time intervals and total water intake per gram. FMU&#95;Osm held greatest utility (area under the receiver operating characteristic curve, sensitivity, and specificity >80%) overall, with the best outcome being FMU&#95;Osm indicating a previous 24-hr osmolality threshold of 500 mOsm/kg (FMU&#95;Osm criterion >710 mOsm/kg and positive likelihood ratio = 5.9). With less effort and cost restriction, FMU is a viable metric to assess underhydration.

A critical issue in addressing medical conditions is measurement. Memory measurement is difficult, especially episodic memory, which is disrupted by many conditions. On-line computer testing can precisely measure and assess several memory functions. This study analyzed memory performances from a large group of anonymous, on-line participants using a continuous recognition task (CRT) implemented at https://memtrax.com. These analyses estimated ranges of acceptable performance and average response time (RT). For 344,165 presumed unique individuals completing the CRT a total of 602,272 times, data were stored on a server, including each correct response (HIT), Correct Rejection, and RT to the thousandth of a second. Responses were analyzed, distributions and relationships of these parameters were ascertained, and mean RTs were determined for each participant across the population. From 322,996 valid first tests, analysis of correctness showed that 63% of these tests achieved at least 45 correct (90%), 92% scored at or above 40 correct (80%), and 3% scored 35 correct (70%) or less. The distribution of RTs was skewed with 1% faster than 0.62 s, a median at 0.890 s, and 1% slower than 1.57 s. The RT distribution was best explained by a novel model, the reverse-exponential (RevEx) function. Increased RT speed was most closely associated with increased HIT accuracy. The MemTrax on-line memory test readily provides valid and reliable metrics for assessing individual episodic memory function that could have practical clinical utility for precise assessment of memory dysfunction in many conditions, including improvement or deterioration over time., Competing Interests: Author CA is the sole owner of MemTrax, LLC, which manages the MemTrax program, and a fee is charged for its use. Other authors (including CA’s father, JA) are unpaid consultants to MemTrax and have no more than that potential conflict of interest pertaining to the manuscript. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Ashford, Clifford, Anand, Bergeron, Ashford and Bayley.)

Background: Recent evidence has demonstrated that athletes are at greater risk for a lower extremity injury following a return-to-sport (RTS) after sport-related concussion (SRC). The reason for this is not completely clear, but it has been hypothesized that persistent deficits in neurocognitive factors may be a contributing factor., Hypothesis/purpose: This study assessed simple reaction time, processing speed, attention, and concentration in a group of athletes, post-concussion upon clearance for RTS for potential deficits that may result in slower reaction time, processing speed, attention, and concentration. The researchers hypothesized that the concussion group would demonstrate worse scores on both assessments compared to a sex-, age-, and sport-matched cohort., Study Design: Case-controlled study., Methods: Twelve participants who had suffered a SRC and eight healthy individuals who were matched to the concussed group by age, sex, and sport were evaluated. Those with a concussion had been cleared for RTS by a licensed healthcare provider. Each participant underwent neurocognitive tests that included a simple reaction time test (SRT) and the King-Devick Test (K-D). Independent t-tests were performed to compare the groups with significance set a priori at p<0.05., Results: There was a significant difference (p =0.024) between groups for SRT with the concussed group demonstrating a better SRT than the control group. There were no significant differences (p =0.939) between the groups for the K-D., Conclusion: With no significant differences between groups in the K-D assessment and, surprisingly, the concussed group having a better SRT compared to the healthy group, our hypothesis was not supported., Clinical Relevance: These specific measures, compounded with extensive post-concussion time lapse until RTS clearance, may have limited capacity in revealing potential persistent deficits in relevant neurocognitive characteristics., Level of Evidence: Level of Evidence 3., Competing Interests: The authors report no conflicts of interest.

The phenomenon of reduced athletic performance following sustained, intense training (Overtraining Syndrome, and OTS) was first recognized more than 90 years ago. Although hundreds of scientific publications have focused on OTS, a definitive diagnosis, reliable biomarkers, and effective treatments remain unknown. The present review considers existing models of OTS, acknowledges the individualized and sport-specific nature of signs/symptoms, describes potential interacting predisposing factors, and proposes that OTS will be most effectively characterized and evaluated via the underlying complex biological systems. Complex systems in nature are not aptly characterized or successfully analyzed using the classic scientific method (i.e., simplifying complex problems into single variables in a search for cause-and-effect) because they result from myriad (often non-linear) concomitant interactions of multiple determinants. Thus, this review 1) proposes that OTS be viewed from the perspectives of complex systems and network physiology, 2) advocates for and recommends that techniques such as trans-omic analyses and machine learning be widely employed, and 3) proposes evidence-based areas for future OTS investigations, including concomitant multi-domain analyses incorporating brain neural networks, dysfunction of hypothalamic-pituitary-adrenal responses to training stress, the intestinal microbiota, immune factors, and low energy availability. Such an inclusive and modern approach will measurably help in prevention and management of OTS., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Armstrong, Bergeron, Lee, Mershon and Armstrong.)

Wang et al. analyze Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment accuracy as screening tests for detecting dementia associated with Alzheimer's disease (AD). Such tests are at the center of controversy regarding recognition and treatment of AD. The continued widespread use of tools such as MMSE (1975) underscores the failure of advancing cognitive screening and assessment, which has hampered the development and evaluation of AD treatments. It is time to employ readily available, efficient computerized measures for population/mass screening, clinical assessment of dementia progression, and accurate determination of approaches for prevention and treatment of AD and related conditions.

Background: A valid, reliable, accessible, engaging, and affordable digital cognitive screen instrument for clinical use is in urgent demand., Objective: To assess the clinical utility of the MemTrax memory test for early detection of cognitive impairment in a Chinese cohort., Methods: The 2.5-minute MemTrax and the Montreal Cognitive Assessment (MoCA) were performed by 50 clinically diagnosed cognitively normal (CON), 50 mild cognitive impairment due to AD (MCI-AD), and 50 Alzheimer's disease (AD) volunteer participants. The percentage of correct responses (MTx-% C), the mean response time (MTx-RT), and the composite scores (MTx-Cp) of MemTrax and the MoCA scores were comparatively analyzed and receiver operating characteristic (ROC) curves generated., Results: Multivariate linear regression analyses indicated MTx-% C, MTx-Cp, and the MoCA score were significantly lower in MCI-AD versus CON and in AD versus MCI-AD groups (all with p≤0.001). For the differentiation of MCI-AD from CON, an optimized MTx-% C cutoff of 81% had 72% sensitivity and 84% specificity with an area under the curve (AUC) of 0.839, whereas the MoCA score of 23 had 54% sensitivity and 86% specificity with an AUC of 0.740. For the differentiation of AD from MCI-AD, MTx-Cp of 43.0 had 70% sensitivity and 82% specificity with an AUC of 0.799, whereas the MoCA score of 20 had 84% sensitivity and 62% specificity with an AUC of 0.767., Conclusion: MemTrax can effectively detect both clinically diagnosed MCI and AD with better accuracy as compared to the MoCA based on AUCs in a Chinese cohort.

Background: The widespread incidence and prevalence of Alzheimer's disease and mild cognitive impairment (MCI) has prompted an urgent call for research to validate early detection cognitive screening and assessment., Objective: Our primary research aim was to determine if selected MemTrax performance metrics and relevant demographics and health profile characteristics can be effectively utilized in predictive models developed with machine learning to classify cognitive health (normal versus MCI), as would be indicated by the Montreal Cognitive Assessment (MoCA)., Methods: We conducted a cross-sectional study on 259 neurology, memory clinic, and internal medicine adult patients recruited from two hospitals in China. Each patient was given the Chinese-language MoCA and self-administered the continuous recognition MemTrax online episodic memory test on the same day. Predictive classification models were built using machine learning with 10-fold cross validation, and model performance was measured using Area Under the Receiver Operating Characteristic Curve (AUC). Models were built using two MemTrax performance metrics (percent correct, response time), along with the eight common demographic and personal history features., Results: Comparing the learners across selected combinations of MoCA scores and thresholds, Naïve Bayes was generally the top-performing learner with an overall classification performance of 0.9093. Further, among the top three learners, MemTrax-based classification performance overall was superior using just the top-ranked four features (0.9119) compared to using all 10 common features (0.8999)., Conclusion: MemTrax performance can be effectively utilized in a machine learning classification predictive model screening application for detecting early stage cognitive impairment.

Introduction: Concussion prevalence in sport is well recognized, so too is the challenge of clinical and return-to-play management for an injury with an inherent indeterminant time course of resolve. A clear, valid insight into the anticipated resolution time could assist in planning treatment intervention., Purpose: This study implemented a supervised machine learning-based approach in modeling estimated symptom resolve time in high school athletes who incurred a concussion during sport activity., Methods: We examined the efficacy of 10 classification algorithms using machine learning for the prediction of symptom resolution time (within 7, 14, or 28 d), with a data set representing 3 yr of concussions suffered by high school student-athletes in football (most concussion incidents) and other contact sports., Results: The most prevalent sport-related concussion reported symptom was headache (94.9%), followed by dizziness (74.3%) and difficulty concentrating (61.1%). For all three category thresholds of predicted symptom resolution time, single-factor ANOVA revealed statistically significant performance differences across the 10 classification models for all learners at a 95% confidence interval (P = 0.000). Naïve Bayes and Random Forest with either 100 or 500 trees were the top-performing learners with an area under the receiver operating characteristic curve performance ranging between 0.656 and 0.742 (0.0-1.0 scale)., Conclusions: Considering the limitations of these data specific to symptom presentation and resolve, supervised machine learning demonstrated efficacy, while warranting further exploration, in developing symptom-based prediction models for practical estimation of sport-related concussion recovery in enhancing clinical decision support.

Background: Memory dysfunction is characteristic of aging and often attributed to Alzheimer's disease (AD). An easily administered tool for preliminary assessment of memory function and early AD detection would be integral in improving patient management., Objective: Our primary aim was to utilize machine learning in determining initial viable models to serve as complementary instruments in demonstrating efficacy of the MemTrax online Continuous Recognition Tasks (M-CRT) test for episodic-memory screening and assessing cognitive impairment., Methods: We used an existing dataset subset (n = 18,395) of demographic information, general health screening questions (addressing memory, sleep quality, medications, and medical conditions affecting thinking), and test results from a convenience sample of adults who took the M-CRT test. M-CRT performance and participant features were used as independent attributes: true positive/negative, percent responses/correct, response time, age, sex, and recent alcohol consumption. For predictive modeling, we used demographic information and test scores to predict binary classification of the health-related questions (yes/no) and general health status (healthy/unhealthy), based on the screening questions., Results: ANOVA revealed significant differences among HealthQScore groups for response time true positive (p = 0.000) and true positive (p = 0.020), but none for true negative (p = 0.0551). Both % responses and % correct had significant differences (p = 0.026 and p = 0.037, respectively). Logistic regression was generally the top-performing learner with moderately robust prediction performance (AUC) for HealthQScore (0.648-0.680) and selected general health questions (0.713-0.769)., Conclusion: Our novel application of supervised machine learning and predictive modeling helps to demonstrate and validate cross-sectional utility of MemTrax in assessing early-stage cognitive impairment and general screening for AD.

Exertional heat stroke (EHS) occurs in distance runners and is a life-threatening condition. A 30-yr-old healthy recreational male distance runner (CR) collapsed at the 12-mile mark in two half marathon races 6 wk apart in fall 2009. In both episodes, CR was found on the ground confused, incoherent, sweaty, and warm to touch. The emergency medical team responded, and he was treated empirically for suspected EHS by cooling en route to the emergency department. In the emergency department, rectal temperatures were 40°C and 40.5°C for each episode, respectively. The first race start temperature was 16°C with 94% relative humidity (RH), and the second was 3°C, 75% RH. Heat tolerance test was within the normal range indicating low EHS risk. A race simulation test (environmental chamber, 25°C, 60% RH) at a treadmill pace of 10.5-12.9 km·h was stopped at 70 min coincident with a rectal temperature of 39.5°C. CR's body weight dropped 3.49 kg with an estimated sweat loss of 4.09 L and an estimated total sweat Na loss of 7610 mg. We recommended that he limit his runs to <1 h and replace salt and fluid during and (mostly) after activity, run with a partner, acclimate to heat before racing, and reduce his pace or stop at the first sign of symptoms. Race simulation testing should be considered in athletes with recurrent EHS to assist with the return-to-activity recommendation.

Objective: To present best-practice recommendations for the prevention, recognition, and treatment of exertional heat illnesses (EHIs) and to describe the relevant physiology of thermoregulation., Background: Certified athletic trainers recognize and treat athletes with EHIs, often in high-risk environments. Although the proper recognition and successful treatment strategies are well documented, EHIs continue to plague athletes, and exertional heat stroke remains one of the leading causes of sudden death during sport. The recommendations presented in this document provide athletic trainers and allied health providers with an integrated scientific and clinically applicable approach to the prevention, recognition, treatment of, and return-to-activity guidelines for EHIs. These recommendations are given so that proper recognition and treatment can be accomplished in order to maximize the safety and performance of athletes., Recommendations: Athletic trainers and other allied health care professionals should use these recommendations to establish onsite emergency action plans for their venues and athletes. The primary goal of athlete safety is addressed through the appropriate prevention strategies, proper recognition tactics, and effective treatment plans for EHIs. Athletic trainers and other allied health care professionals must be properly educated and prepared to respond in an expedient manner to alleviate symptoms and minimize the morbidity and mortality associated with these illnesses.

Unlabelled: Football players are subjected to repetitive impacts that may lead to brain injury and neurologic dysfunction. Knowledge about head impact exposure (HIE) and consequent neurologic function among youth football players is limited., Purpose: This study aimed to measure and characterize HIE of youth football players throughout one season and explore associations between HIE and changes in selected clinical measures of neurologic function., Methods: Twenty-two youth football players (11-13 yr) wore helmets outfitted with a head impact telemetry (HIT) system to quantify head impact frequency, magnitude, duration, and location. Impact data were collected for each practice (27) and game (9) in a single season. Selected clinical measures of balance, oculomotor performance, reaction time, and self-reported symptoms were assessed before and after the season., Results: The median individual head impacts per practice, per game, and throughout the entire season were 9, 12, and 252, respectively. Approximately 50% of all head impacts (6183) had a linear acceleration between 10g and 20g, but nearly 2% were greater than 80g. Overall, the head impact frequency distributions in this study population were similar in magnitude and location as in high school and collegiate football, but total impact frequency was lower. Individual changes in neurologic function were not associated with cumulative HIE., Conclusion: This study provides a novel examination of HIE and associations with short-term neurologic function in youth football and notably contributes to the limited HIE data currently available for this population. Whereas youth football players can experience remarkably similar head impact forces as high school players, cumulative subconcussive HIE throughout one youth football season may not be detrimental to short-term clinical measures of neurologic function.

Hydration is arguably among the foremost priorities youth athletes, parents, and coaches habitually consider as vital for sports. Insufficient hydration and a resultant measurable sweat-induced body water deficit can negatively affect performance and, in some athletic scenarios, can be a danger to a young athlete's health and safety, especially during vigorous physical activity in a warm-to-hot environment. Accordingly, it is essential to be well hydrated prior to practice, training, and competition and minimize total body water deficits incurred while being mindful of the greater sweat losses and hydration needs/challenges that accompany physical growth and maturation. Informed clinicians can play a key role as trusted resources in providing the most effective guidelines and making the best overall individual recommendations regarding hydration for youth athletes.

The health, fitness and other advantages of youth sports participation are well recognised. However, there are considerable challenges for all stakeholders involved-especially youth athletes-in trying to maintain inclusive, sustainable and enjoyable participation and success for all levels of individual athletic achievement. In an effort to advance a more unified, evidence-informed approach to youth athlete development, the IOC critically evaluated the current state of science and practice of youth athlete development and presented recommendations for developing healthy, resilient and capable youth athletes, while providing opportunities for all levels of sport participation and success. The IOC further challenges all youth and other sport governing bodies to embrace and implement these recommended guiding principles., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.)

Objectives: This study examined the diagnostic benefit of using dual-task interference balance testing in young concussion patients and the longitudinal changes in postural stability that occur relative to other standard clinical assessments of concussion injury., Design: Longitudinal, case-control., Methods: Eighteen patients (16.6 (1.6)y) diagnosed with a concussion provided 22 separate ratings to characterize the severity of their current concussion-related symptoms and were evaluated for postural stability at each of four clinical visits. Twenty-six injury-free adolescents (17 (2.8)y) performed balance testing on two occasions, separated by ∼1 week., Results: There was a progressive decrease in self-reported symptoms from visit 1 to visit 4 (P<0.0001-0.001). A similar improvement occurred in postural stability, indicated by 95% ellipse area and velocity. However, the differences in ellipse area and velocity were significant only between visit 1 and the rest of the visits as a whole (P<0.0001-0.05). There was a significant difference between concussion patients and healthy, injury-free participants in ellipse area and velocity during visit 1. A group difference was also observed in ellipse area on visit 2, but only during the two balance tests that involved a concomitant secondary cognitive task., Conclusions: Improvements in postural stability coincide with reductions in reported symptoms, though apparent recovery of these selected measures of postural stability seemingly occurs sooner. Because of the distinguishing time course of recovery indicated by dual-task interference balance testing, this type of balance testing assessment may be particularly valuable in evaluating integrated functional impairment and recovery in young concussion patients., (Copyright © 2013 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.)

We assessed 10 youth football players (13.4 ± 0.7 y) immediately before and after their season to explore the effects of football participation on selected clinical measures of neurologic function. Postseason postural stability in a closed-eye condition was improved compared to preseason (P = .017). Neurocognitive testing with the Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) battery revealed that reaction time was significantly faster at postseason (P = .015). There were no significant preseason versus postseason differences in verbal memory (P = .507), visual memory (P = .750), or visual motor speed (P = .087). Oculomotor performance assessed by the King-Devick test was moderately to significantly improved (P = .047-.115). A 12-week season of youth football did not impair the postural stability, neurocognitive function, or oculomotor performance measures of the players evaluated. Though encouraging, continued and more comprehensive investigations of this at-risk population are warranted., (© The Author(s) 2013.)

Synopsis: Running well and safely in the heat is challenging for all runners, from recreational to elite. As environmental heat stress (heat stress modulated or augmented by air temperature, humidity, wind speed, and solar radiation) and the intensity and duration of a training run or race increase, so are metabolic heat production, the parallel need for heat transfer from the body to maintain thermal equilibrium, the consequent increase in blood flow to the skin, and the concomitant sweating response progressively and proportionally amplified. An accumulating total body-water deficit from extensive sweating and escalating level of cardiovascular and thermal strain will, in due course, considerably challenge a runner's physiology, perception of effort, and on-course well-being and performance. However, with the appropriate preparation and modifications to planned running intensity and distance, runners can safely tolerate and effectively train and compete in a wide range of challenging environmental conditions. Clinicians play a key role in this regard as an effective resource for providing the most effective guidelines and making the best overall individual recommendations regarding training and competing in the heat.

Competitive tennis in the heat can prompt substantial sweat losses and extensive consequent body water and electrolyte deficits, as well as a level of thermal strain that considerably challenges a player's physiology, perception of effort, and on-court well-being and performance. Adequate hydration and optimal performance can be notably difficult to maintain when multiple same-day matches are played on successive days in hot weather. Despite the recognised effects of the heat, much more research needs to be carried out to better appreciate the broader scope and full extent of the physiological demands and hydration and thermal strain challenges facing junior and adult players in various environments, venues and competition scenarios. However, certain recommendations of best practices should be emphasised to minimise exertional heat illness risk and improve player safety, well-being and on-court performance.

Prevention of musculoskeletal injuries (MSKI) is critical in both civilian and military populations to enhance physical performance, optimize health, and minimize health care expenses. Developing a more unified approach through addressing identified movement impairments could result in improved dynamic balance, trunk stability, and functional movement quality while potentially minimizing the risk of incurring such injuries. Although the evidence supporting the utility of injury prediction and return-to-activity readiness screening tools is encouraging, considerable additional research is needed regarding improving sensitivity, specificity, and outcomes, and especially the implementation challenges and barriers in a military setting. If selected current functional movement assessments can be administered in an efficient and cost-effective manner, utilization of the existing tools may be a beneficial first step in decreasing the burden of MSKI, with a subsequent focus on secondary and tertiary prevention via further assessments on those with prior injury history.

Unlabelled: The King-Devick (KD) oculomotor test has recently been advocated for sideline diagnosis of concussion. Although visual processing and performance are often impaired in concussion patients, the utility of KD as a concussion diagnostic tool is not validated., Purpose: To examine the diagnostic value of KD, by comparing KD with post-concussion symptom scale (PCSS) and ImPACT® composite scores. We hypothesized that KD would be correlated with visual motor speed/memory (VMS, VIS) and reaction time (RT), because all require cognitive visual processing. We also expected parallel changes in KD and PCSS across recovery., Methods: Thirty-five concussed individuals (12-19 y; 18 females, 17 males) were evaluated with PCSS, ImPACT® composite and KD scores over four clinical visits (V)., Results: KD times improved with each visit (ΔV1-V2: 7.86±11.82; ΔV2-V3: 9.17 ± 11.07; ΔV3-V4: 5.30 ± 7.87 s) and paralleled improvements in PCSS (ΔV1-V2: 8.97 ± 20.27; ΔV2-V3: 8.69 ± 14.70; ΔV3-V4: 6.31 ± 7.71), RT (ΔV1-V2: 0.05 ± 0.21; ΔV2-V3: 0.09 ± 0.19; ΔV3-V4 0.03 ± 0.07) and VMS (ΔV1-V2: -5.27 ± 6.98; ΔV2-V3: -2.61 ± 6.48; ΔV3-V4: -2.35 ± 5.22). Longer KD times were associated with slower RT (r = 0.67; P<0.0001) and lower VMS (r = -0.70; P<0.0001), respectively., Conclusion: Cognitive visual performance testing using KD has utility in concussion evaluation. Validation would further establish KD as an effective ancillary tool in longitudinal concussion management and research., (© 2013 Elsevier B.V. All rights reserved.)

Objectives: After reading this article, readers should 1. Appreciate that exertional heatstroke is the leading cause of preventable death in youth sports.2. Know the importance of progressive acclimatization to minimize the risk of exertional heat illness in youth sports.3. Be able to identify other contributing risk factors and effective ways to improve exercise-heat tolerance and reduce exertional heat illness risk in youth sports.4. Be prepared to educate others on their roles and responsibilities in improving safety and well-being of youth participating in outdoor sports in the heat.

Context: Evolving concussion diagnosis/management tools and guidelines make Knowledge Transfer and Exchange (KTE) to practitioners challenging., Objective: Identify sports concussion knowledge base and practise patterns in two family physician populations; explore current/preferred methods of KTE., Design: A cross-sectional study., Setting: Family physicians in Alberta, Canada (CAN) and North/South Dakota, USA., Participants: CAN physicians were recruited by mail: 2.5% response rate (80/3154); US physicians through a database: 20% response rate (109/545). INTERVENTION/INSTRUMENT: Online survey. MAIN AND SECONDARY OUTCOME MEASURES: Diagnosis/management strategies for concussions, and current/preferred KTE., Results: Main reported aetiologies: sports/recreation (52.5% CAN); organised sports (76.5% US). Most physicians used clinical examination (93.8% CAN, 88.1% US); far fewer used the Sport Concussion Assessment Tool (SCAT1/SCAT2) and balance testing. More US physicians initially used concussion-grading scales (26.7% vs 8.8% CAN, p=0.002); computerised neurocognitive testing (19.8% vs 1.3% CAN; p<0.001) and Standardised Assessment of Concussion (SAC) (21.8% vs 7.5% CAN; p=0.008). Most prescribed physical rest (83.8% CAN, 75.5% US), while fewer recommended cognitive rest (47.5% CAN, 28.4% US; p=0.008). Return-to-play decisions were based primarily on clinical examination (89.1% US, 73.8% CAN; p=0.007); US physicians relied more on neurocognitive testing (29.7% vs 5.0% CAN; p<0.001) and recognised guidelines (63.4% vs 23.8% CAN; p<0.001). One-third of Canadian physicians received KTE from colleagues, websites and medical school training. Leading KTE preferences included Continuing Medical Education (CME) courses and online CME., Conclusions: Existing published recommendations regarding diagnosis/management of concussion are not always translated into practise, particularly the recommendation for cognitive rest; predicating enhanced, innovative CME initiatives.

Introduction: An estimated 300 million people worldwide have sickle cell trait (SCT). Although largely benign, SCT has been associated with exertional rhabdomyolysis and exercise-related sudden death in warfighters/athletes (WA). The National Collegiate Athletic Association's policy to confirm a student athlete's SCT status during their preparticipation medical examination prompted reaction from some organizations regarding the rationale and ethical justification of the policy., Methods: On September 26 and 27, 2011, a summit, composed of military and civilian experts in sports medicine and SCT, was convened at the Uniformed Services University in Bethesda, MD. The expert panel was charged with two objectives: 1) to provide specific recommendations to further mitigate the apparent risk with strenuous exercise in WA with SCT and 2) to develop clinical guidelines to identify, treat, and return to duty/play WA suspected to have incurred nonfatal sickle cell collapse., Results: New terminology is introduced, areas of current controversy are explored, consensus recommendations for mitigating risk and managing the WA with SCT are reviewed, and important areas for future research are identified., Conclusion: Further research is needed before conclusions can be drawn regarding the etiology of the increased death rate observed in WA with SCT, and the possibility exists that SCT is a surrogate for as yet another contributing factor for the unexplained deaths.

Although many elite sporting events occur in climate-controlled venues, some athletes train and compete in environments that can potentially pose a risk to the athlete's health. In particular, athletes in aquatics, track and field, tennis, football and triathlon can be exposed to extreme heat during competition or while training. The International Federations responsible for these sports are aware of these health risks and have implemented measures to help protect the health of their athletes. This review paper outlines the sport-specific environmental health risks and the safety standards implemented to safeguard athlete health.