BackgroundProfessional soccer players are advised to consume 3–8 g kg–1 body mass day–1 of carbohydrate (CHO) on the basis of training demands, fixture schedule and personal objectives. However, owing to the lack of randomized controlled trials on elite players, these guidelines largely rely on data interpretation and practitioner experience.ObjectiveTo identify the gaps in existing literature that inform CHO guidelines for soccer players.MethodsA scoping review was conducted without date restrictions up to 21 March 2024, employing a three-step search strategy to identify relevant English-language primary and secondary articles through PubMed and reference searching. Data were extracted using a standardized audit tool from studies assessing direct and indirect impacts of CHO on soccer players’ performance and health.ResultsWithin 258 studies identified, experimental studies were the most common (~ 36%), followed by observational (~ 33%) and narrative reviews (~ 26%), with systematic reviews, meta-analyses and case studies making up the rest (~ 5%). Most observational studies were field-based (~ 98%), while experimental studies were laboratory-based (~ 75%). Among 4475 participants, ~ 16% were female, and only ~ 12% of the original research was exclusively conducted on female players. Observational studies included developmental (~ 52%) and professional players (~ 31%), whereas experimental studies primarily featured recreationally active (~ 40%) and collegiate/university participants (~ 26%). Key research topics were ‘dietary intake’ (~ 52%) and “energy expenditure and dietary intake” (~ 30%) for observational studies and ‘CHO interventions’ (~ 74%) for experimental studies. Only eight experimental studies exclusively involved professional players, focusing on CHO intervention (n = 7) and CHO co-ingestion (n = 1). Narrative reviews were published in journals with higher impact factor (4.1 ± 6.4) than were observational studies (3.2 ± 1.6, p < 0.001) and experimental studies (3.4 ± 1.6, p < 0.001). Narrative reviews had the most studies, with Altmetric scores ≥ 20 (n = 26), followed by experimental (n = 16) and observational studies (n = 14).ConclusionsCurrent CHO guidelines for elite soccer players lack experimental research specific to professional and world-class players. More field-based experimental trials involving elite soccer players are required to ensure evidence-based CHO recommendations.

Peripheral blood stem cell (PBSC) donation is the primary procedure used to collect haemopoietic stem cells (HSCs) for transplantation in individuals with haematological malignancies. More than 90,000 HSC transplants take place globally each year, and there is an increasing need to guarantee HSC mobilisation, improve tolerability to apheresis, and optimise immune reconstitution. Currently, mobilisation of HSCs depends upon pharmacological agents, with donors inactive during their subsequent apheresis. A successful yield of HSCs is not always achieved, and greater efficiency of collection procedures would improve the donors’ safety and experience, along with the overall functioning of apheresis departments. The mobilisation of immune cells during bouts of exercise has been increasingly studied over the past 40 years. Exercise enriches peripheral blood with HSCs and immune cells such as cytolytic natural killer cells, and these may impact upon collection efficiency and patient outcomes following transplantation. Using exercise in conjunction with routine pharmaceutical agents may meet these needs. This article describes the impact of exercise on the quantity and engraftment potential of HSCs. Given that PBSC collections take on average 3–4 h per day per donor, and often consecutive days to complete, particular attention is paid to adopting interval exercise in this setting. Moreover, practical and safety considerations for allogeneic and autologous donors are discussed. ‘Intra-apheresis cycling’ is proposed as a feasible adjunctive strategy to evoke clinically significant improvements in the quality of the immune graft. Further research is needed to validate this concept in conjunction with routine mobilisation agents.

BackgroundDietary nitrate (NO3−) supplementation is purported to benefit exercise performance. However, previous studies have evaluated this nutritional strategy with various performance outcomes, exercise tasks, and dosing regimens, often yielding inconsistent results that limit the generalizability of the findings.ObjectiveWe aimed to synthesize the available evidence regarding the effect of NO3− supplementation on 11 domains of exercise performance.MethodsAn umbrella review was reported in accordance with the Preferred Reporting Items for Overviews of Reviews guideline. Seven databases (MEDLINE, EMBASE, Cochrane Database, CINAHL, Scopus, SPORTDiscus, and Web of Science) were searched from inception until July 2024. Systematic reviews with meta-analyses comparing NO3− supplementation and placebo-controlled conditions were included. Literature search, data extraction, and methodological quality assessment (A Measurement Tool to Assess Systematic Reviews Assessing the Methodological quality of SysTemAtic Review [AMSTAR-2]) were conducted independently by two reviewers.ResultsTwenty systematic reviews with meta-analyses, representing 180 primary studies and 2672 unique participants, met the inclusion criteria. Our meta-analyses revealed mixed effects of NO3− supplementation. It improved time-to-exhaustion tasks [standardized mean difference (SMD): 0.33; 95% confidence interval (CI) 0.19–0.47] with subgroup analyses indicating more pronounced improvements when a minimum dose of 6 mmoL/day (372 mg/day) and chronic (> 3 days) supplementation protocol was implemented. Additionally, ergogenic effects of NO3− supplementation were observed for total distance covered (SMD: 0.42; 95% CI 0.09–0.76), muscular endurance (SMD: 0.48; 95% CI 0.23–0.74), peak power output (PPO; SMD: 0.25; 95% CI 0.10 to 0.39), and time to PPO (SMD: − 0.76; 95% CI − 1.18, − 0.33). However, no significant improvements were found for other performance outcomes (all p > 0.05). The AMSTAR-2 ratings of most included reviews ranged from low to critically low.ConclusionsThis novel umbrella review with a large-scale meta-analysis provides an updated synthesis of evidence on the effects of NO3− supplementation across various aspects of exercise performance. Our review also highlights significant methodological quality issues that future systematic reviews in this field should address to enhance the reliability of evidence.Clinical Trial RegistrationThis study was registered in the International Prospective Register of Systematic Review (PROSPERO) database (registration number: CRD42024577461).

Following anterior cruciate ligament (ACL) injury, quadriceps muscle atrophy persists despite rehabilitation, leading to loss of lower limb strength, osteoarthritis, poor knee joint health and reduced quality of life. However, the molecular mechanisms responsible for these deficits in hypertrophic adaptations within the quadriceps muscle following ACL injury and reconstruction are poorly understood. While resistance exercise training stimulates skeletal muscle hypertrophy, attenuation of these hypertrophic pathways can hinder rehabilitation following ACL injury and reconstruction, and ultimately lead to skeletal muscle atrophy that persists beyond ACL reconstruction, similar to disuse atrophy. Numerous studies have documented beneficial roles of nutritional support, including nutritional supplementation, in maintaining and/or increasing muscle mass. There are three main mechanisms by which nutritional supplementation may attenuate muscle atrophy and promote hypertrophy: (1) by directly affecting muscle protein synthetic machinery; (2) indirectly increasing an individual’s ability to work harder; and/or (3) directly affecting satellite cell proliferation and differentiation. We propose that nutritional support may enhance rehabilitative responses to exercise training and positively impact molecular machinery underlying muscle hypertrophy. As one of the fastest growing knee injuries worldwide, a better understanding of the potential mechanisms involved in quadriceps muscle deficits following ACL injury and reconstruction, and potential benefits of nutritional support, are required to help restore quadriceps muscle mass and/or strength. This review discusses our current understanding of the molecular mechanisms involved in muscle hypertrophy and disuse atrophy, and how nutritional supplements may leverage these pathways to maximise recovery from ACL injury and reconstruction.

BackgroundThe incidence and risk factors for sport-related concussion (SRC) associated with contact and collision invasion sports (CCIS) in female youth are unclear.ObjectivesThis systematic review aimed to identify (i) the incidence of and (ii) risk factors for SRC in female youth athletes playing CCIS.MethodsA systematic search of PubMed, CINAHL, Embase, SPORTDiscus and ProQuest to 8 May, 2024 was conducted. Two reviewers independently screened articles against eligibility criteria and assessed risk of bias (Joanna Briggs Institute Critical Appraisal Tool). Aetiological or intervention studies reporting on SRC incidence or risk factors in female youth athletes (aged 13–19 years and under) participating in CCIS were included. Meta-analyses were conducted to explore SRC incidence and risk factors. For each meta-analysis of SRC incidence rate, sub-group analyses were conducted by sport. Where heterogeneity was above 60% for the meta-analysis of SRC risk/protective factors, sensitivity analyses were conducted.ResultsThe search yielded 4509 articles; 66 were included. Sport-related concussion incidence or risk factor data for nine CCIS were extracted. Pooled estimates revealed SRC incidence for female youth athletes in CCIS combined was 0.50/1000 match and practice hours (95% confidence interval [CI] 0.34–0.66). When examined by sport classification, SRC incidence in contact invasion sports was 0.12/1000 match and practice hours (95% CI 0.03–0.21), and in collision invasion sports was 2.08/1000 match and practice hours (95% CI 0.90–3.25). Sub-group analysis by individual sport revealed female youth soccer players had the highest overall SRC incidence rate (0.89/1000 match and practice hours, 95% CI − 0.19 to 1.97) amongst contact sports, and rugby union players had the highest overall SRC incidence rate (4.04/1000 match and practice hours, 95% CI 3.03–5.05) among collision sports. Forty-five studies (68%) reported SRC risk factor data, investigating 12 different potential risk factors. Female youth sustained over 7.5 times the rate of SRC in matches compared with practice (incidence rate ratio 7.52, 95% CI 6.32–8.95, p < 0.01) when competing in CCIS; however, considerable heterogeneity existed (I2 = 84.98%). When exploring potential risk factors, no significant difference was found in SRC rate between female youth lacrosse players wearing versus not wearing headgear (p = 0.07). No significant difference was found in SRC rates between female youth athletes competing in younger versus older age groups (incidence rate ratio 0.91, 95% CI 0.52–1.61, p = 0.48, I2 = 0.00%). Insufficient evidence was available to examine remaining risk factors.ConclusionsThis meta-analysis revealed SRC in female youth playing CCIS was higher than previously reported, with SRC rates higher in matches than practice. Soccer had the highest SRC incidence rate for female youth athletes competing in contact invasion sports, whilst rugby union demonstrated the highest SRC incidence rates for collision invasion sports. The results of this review should be interpreted with caution given the lack of representation from some common CCIS codes. Further research is required to examine SRC risk factors in female youth athletes participating in CCIS.Clinical Trial RegistrationOSF Registration: osf.io/s573v.

ObjectivesThe purpose of this study was to investigate head kinematic variables in elite men’s and women’s rugby union and their ability to predict player removal for an off-field (HIA1) head injury assessment.MethodsInstrumented mouthguard (iMG) data were collected for 250 men and 132 women from 1865 and 807 player-matches, respectively, and synchronised to video-coded match footage. Head peak resultant linear acceleration (PLA), peak resultant angular acceleration (PAA) and peak change in angular velocity (dPAV) were extracted from each head acceleration event (HAE). HAEs were linked to documented HIA1 events, with ten logistical regression models for men and women, using a random subset of non-case HAEs, calculated to identify kinematic variables associated with HIA1 events. Receiver operating characteristic curves (ROC) were used to describe thresholds for HIA1 removal.ResultsIncreases in PLA and dPAV were significantly associated with an increasing likelihood of HIA1 removal in the men’s game, with an OR ranging from 1.05–1.12 and 1.13–1.18, respectively. The optimal values to maximise for both sensitivity and specificity for detecting an HIA1 were 1.96 krad⋅s−2, 24.29 g and 14.75 rad⋅s−1 for PAA, PLA and dPAV, respectively. Only one model had any significant variable associated with increasing the likelihood of a HIA1 removal in the women’s game—PAA with an OR of 8.51 (1.23–58.66). The optimal values for sensitivity and specificity for women were 2.01 krad⋅s−2, 25.98 g and 15.38 rad⋅s−1 for PAA, PLA and dPAV, respectively.ConclusionPLA and dPAV were predictive of men’s HIA1 events. Further HIA1 data are needed to understand the role of head kinematic variables in the women’s game. The calculated spectrum of sensitivity and specificity of iMG alerts for HIA1 removals in men and women present a starting point for further discussion about using iMGs as an additional trigger in the existing HIA process.

Everyday human interactions require observers to anticipate the actions of others (e.g., when walking past another in a corridor or choosing where to hit a ground stroke in tennis). Yet, experimental paradigms that aim to examine anticipation continue to use simplistic designs that are not interactive and therefore fail to account for the real-life, social nature of these interactions. Here we propose a fundamental, paradigmatic shift toward a “dynamic interactive anticipation” paradigm that models real-life interactions. We propose that it will change the way behavioral experimentalists study anticipation and spark theory development by unravelling the mechanisms underlying anticipation in real-time interactions.

BackgroundThe rapid growth of women's rugby union has underscored the need for female-specific player welfare protocols, particularly regarding the risk of head injuries. Instrumented mouthguards (iMGs) play a vital role in gathering comprehensive data on head acceleration events (HAEs), including their frequency, magnitude, and spatial distribution during games and training. By doing so, iMGs offer valuable context for circumstances in women's matches that may increase player risk.ObjectivesThe study aimed to contextualize HAEs in female community rugby players using instrumented mouthguards and video review.MethodsThis prospective, observational cohort study involved 332 female rugby players across 38 matches and 80 training sessions during the 2021/2022 seasons. Players were representative of four playing grades: U13 (N = 9), U15 (N = 111), U19 (N = 95) and Premier women (N = 115). HAEs were recorded using boil-and-bite iMGs, with a single-axis recording threshold of 5 g. The incidence and prevalence of HAEs was expressed by grade, years of experience, playing positions, and session types (match or training). The effect of playing grade and previous playing experience on HAE propensity during tackles and rucks was also examined.ResultsThroughout the study, 9151 iMG events over 5 g were recorded, with 80% verified for analysis. Overall, the incidence rate (IR) was highest for HAEs between 10 and 29 g, 12–18 times higher than the IR for > 30-g events. Premier grade players had the highest weekly HAE load (26.2 per player per week) and the highest prevalence of players (49%) exposed to events over 30 g. An inverse relationship was found between years of rugby experience and peak angular acceleration (PAA) in U13–U19 players (p = 0.002, 95% CI [47,177 rads/s2]), showing that more experienced school-age players had lower rotational acceleration during HAEs. However, propensity for HAEs in tackle events was highest in Premier players with > 9 years of experience compared with U13–U19 grade players with similar years of experience (RR = 1.21, 95% CI 1.06–1.37; p = 0.004). Ball carries consistently resulted in the highest propensity of events over 30 g, regardless of playing grade or experience.ConclusionsThis research presents unique information regarding head accelerations that occur during women’s community rugby matches and practices. The results have significant implications for recognising populations that are at the highest risk of experiencing high cumulative and acute head accelerations. The findings may assist in managing training loads and instructing skill execution in high-risk activities, particularly for younger players who are new to the sport.Consideration of playing grade, experience, and contact phases is crucial for understanding head acceleration exposure and injury risk in female rugby players. These insights can inform injury prevention strategies.

Coverage of problems relating to mental health and well-being is gaining ground in the sports sector today, both in the media and in the scientific literature. Despite exposure to numerous stressors and suffering from poor mental health, coaches have in general been largely overlooked in the scientific literature. Previous studies have mainly focused upon athlete populations. The absence of research means that there are real shortcomings in both understanding the mechanisms involved in the deterioration of coaches’ mental health and well-being and in the lack of specific support systems available. This paper first describes findings from the recent, albeit quite scarce, research investigating mental health and well-being in coaches. It then proposes a number of avenues for research and support protocols, both of which are currently ongoing at the French Football Federation Research Centre. The aim is to help support these key participants in the sports sector who arguably have not been given sufficient consideration until now.

BackgroundThe inclusion of skateboarding in the Olympics suggests that athletes and coaches are seeking ways to enhance their chances of succeeding on the world stage. Understanding what constitutes performance, and what physical, neuromuscular, and biomechanical capacities underlie it, is likely critical to success.ObjectiveThe aim was to overview the current literature and identify knowledge gaps related to competitive skateboarding performance and associated physical, technical, and tactical demands of Olympic skateboarding disciplines.MethodsA systematic scoping review was performed considering the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (Extension for Scoping Reviews) guidelines. Data sources were MEDLINE (Ovid), Scopus, SPORTDiscus, and PubMed. We included all peer-reviewed literature after 1970 describing the physiological, neuromuscular, biomechanical, and/or tactical aspects of skateboarding.ResultsNineteen original articles explored the physiological (n = 9), biomechanical (n = 8), and technical (n = 10) demands of skateboarding. No research explored the tactical demands of competition. Moreover, although competitive males (n = 2 studies) and females (n = 1 study) were recruited as participants, no research directly related skateboarding demands to performance success in competitive environments.ConclusionsUltimately, what constitutes and distinguishes competitive skateboarding is unexplored. There is some evidence indicating aspects of the sport require flexibility and elevated and fast force output of the lower limbs, which may be valuable when attempting to maximise ollie height. Nonetheless, a lack of ecological validity, such as using static ollie tests as opposed to rolling, restricted our ability to provide practical recommendations, and inconsistency of terminology complicated delineating discipline-specific outcomes. Future researchers should first look to objectively identify what skaters do in competition before assessing what qualities enable their performance.