Assessment of Cardiorespiratory and Metabolic Contributions in an Extreme Intensity CrossFit® Benchmark Workout.

Our purpose was to characterize the oxygen uptake kinetics (VO2), energy systems contributions and total energy expenditure during a CrossFit® benchmark workout performed in the extreme intensity domain. Fourteen highly trained male CrossFitters, aged 28.3 ± 5.4 years, with height 177.8 ± 9.4 cm, body mass 87.9 ± 10.5 kg and 5.6 ± 1.8 years of training experience, performed the Isabel workout at maximal exertion. Cardiorespiratory variables were measured at baseline, during exercise and the recovery period, with blood lactate and glucose concentrations, including the ratings of perceived exertion, measured pre- and post-workout. The Isabel workout was 117 ± 10 s in duration and the VO2 peak was 47.2 ± 4.7 mL·kg-1·min-1, the primary component amplitude was 42.0 ± 6.0 mL·kg-1·min-1, the time delay was 4.3 ± 2.2 s and the time constant was 14.2 ± 6.0 s. The accumulated VO2 (0.6 ± 0.1 vs. 4.8 ± 1.0 L·min-1) value post-workout increased substantially when compared to baseline. Oxidative phosphorylation (40%), glycolytic (45%) and phosphagen (15%) pathways contributed to the 245 ± 25 kJ total energy expenditure. Despite the short ~2 min duration of the Isabel workout, the oxygen-dependent and oxygen-independent metabolism energy contributions to the total metabolic energy release were similar. The CrossFit® Isabel requires maximal effort and the pattern of physiological demands identifies this as a highly intensive and effective workout for developing fitness and conditioning for sports.

Using artificial intelligence for exercise prescription in personalised health promotion: A critical evaluation of OpenAI's GPT-4 model.

The rise of artificial intelligence (AI) applications in healthcare provides new possibilities for personalized health management. AI-based fitness applications are becoming more common, facilitating the opportunity for individualised exercise prescription. However, the use of AI carries the risk of inadequate expert supervision, and the efficacy and validity of such applications have not been thoroughly investigated, particularly in the context of diverse health conditions. The aim of the study was to critically assess the efficacy of exercise prescriptions generated by OpenAI's Generative Pre-Trained Transformer 4 (GPT-4) model for five example patient profiles with diverse health conditions and fitness goals. Our focus was to assess the model's ability to generate exercise prescriptions based on a singular, initial interaction, akin to a typical user experience. The evaluation was conducted by leading experts in the field of exercise prescription. Five distinct scenarios were formulated, each representing a hypothetical individual with a specific health condition and fitness objective. Upon receiving details of each individual, the GPT-4 model was tasked with generating a 30-day exercise program. These AI-derived exercise programs were subsequently subjected to a thorough evaluation by experts in exercise prescription. The evaluation encompassed adherence to established principles of frequency, intensity, time, and exercise type; integration of perceived exertion levels; consideration for medication intake and the respective medical condition; and the extent of program individualization tailored to each hypothetical profile. The AI model could create general safety-conscious exercise programs for various scenarios. However, the AI-generated exercise prescriptions lacked precision in addressing individual health conditions and goals, often prioritizing excessive safety over the effectiveness of training. The AI-based approach aimed to ensure patient improvement through gradual increases in training load and intensity, but the model's potential to fine-tune its recommendations through ongoing interaction was not fully satisfying. AI technologies, in their current state, can serve as supplemental tools in exercise prescription, particularly in enhancing accessibility for individuals unable to access, often costly, professional advice. However, AI technologies are not yet recommended as a substitute for personalized, progressive, and health condition-specific prescriptions provided by healthcare and fitness professionals. Further research is needed to explore more interactive use of AI models and integration of real-time physiological feedback.

Swimming sprint performance depends on upper/lower limbs strength and swimmers level.

Swimming performance is likely influenced by strength, but differences between butterfly, backstroke, breaststroke and front crawl, as well as between novice and expert swimmers, are unclear. We have examined the associations between sprint performances, upper and lower limb strength, and anthropometric characteristics in 14 (six males and eight females) non-elite and 16 (nine males and seven females) elite-level swimmers. After an anthropometric characterisation, participants performed four 25 m maximal swims (one per technique) with 10 min intervals, right and left shoulder flexion/extension isokinetic testing at 90 and 300º/s angular velocities and three countermovement jumps. Pearson correlation analysis showed that sprint times were moderate-largely negatively correlated with upper and lower limb strength and power (r ± 95%CI = 0.39 ± 0.26-0.77 ± 0.13, p < 0.05). Elite swimmers higher strength levels were associated with longer stroke length in butterfly and front crawl, and with higher stroke rate in backstroke and breaststroke (r ± 95%CI = 0.37 ± 0.32-0.68 ± 0.21; p < 0.05). Butterfly, backstroke and front crawl sprint times were moderate-largely negatively related with arm span (r ± 95%CI = 0.37 ± 0.26, 0.39 ± 0.25 and 0.69 ± 0.17, p < 0.05). The predictive model indicated that higher dry-land strength values distinguished elite from non-elite swimmers (r2 = 0.67-0.81; p < 0.001). This association was not observed per performance level and per sex, confirming that sprint swimming performance levels can be differentiated by dry-land strength testing.

Immunomodulatory effects of fucoidan in recreationally active adult males undertaking 3-weeks of intensified training.

The aim of the current study was to determine whether daily fucoidan supplementation (Undaria pinnatifida extract containing >85% fucoidan, 1 g/day) for three-weeks in a double blind-placebo controlled cross-over trial (ACTRN12621000872831) could modulate alterations in faecal (calprotectin, lysozyme and IgA) and salivary (lactoferrin, lysozyme and IgA) markers of mucosal immune competence typically observed in response to both acute physical activity, and a period of intensified exercise training, in healthy recreationally active men (n = 12). Participants responded positively to the intensified training with 16-19% improvement in mean power that was not different between supplement groups. Faecal biomarkers and concentrations of lactoferrin, lysozyme and IgA from resting saliva samples were largely stable over the supplementation period. Concentrations of salivary biomarkers varied significantly over time in response to acute exercise, however differences between supplementation groups were modest. For salivary lysozyme, there was a trend for a lower magnitude of increase post-exercise (p = 0.08) and limited return towards pre-exercise in response to fucoidan. For salivary IgA, a greater acute exercise response was noted for IgA in response to fucoidan (~2.7-fold higher; p = 0.02). Different dosage and supplementation protocols and inclusion of additional immune markers should be considered in subsequent assessments of any potential benefits of fucoidan supplementation in healthy active adults.

Predicting the unpredictable: analysing the entropy and spatial distribution of ball movement patterns in field hockey.

Analysing the ball movement patterns of team invasion sports provides practical insight into successful strategies by identifying how and where to move the ball to create goal scoring opportunities. The aim of this study was to analyse the entropy and spatial distribution of ball movement patterns in international field hockey teams. A notational analysis system was developed in SportsCode to analyse 131 matches (n = 57 men, n = 74 women) from the 2019 Pro League tournament. The start and end location of each ball movement and the outcome of each play was recorded. Calculated variables included game possession (%), entropy, possession per zone (%) and progression rates. Decision trees identified that higher circle possession and direct movements to goal from deep attack, and lower build attack and build defence entropy, were the strategies most likely to lead to goal shots. However, teams should be unpredictable when the opposition are organised to maintain possession and unbalance the defence. Match context only had small effects on ball movement strategies highlighting there is more than one way to be successful. Executing strategies that exploit these factors should lead to greater attacking opportunities and success. Analysing the dynamic, complexity of international hockey allows coaches to prepare specific strategies for individual teams.

Technical Skills Influences on Front Crawl Tumble Turn Performance in Elite Female Swimmers.

The objective of this research was to compare technical skills composed of kinematic and kinetic variables in the complex motor task of a tumble turn between 9 elites and 9 sub-elite female swimmers. The best tumble turn among three attempts was analyzed using a three-dimensional underwater protocol. A total of 37 kinematic variables were derived from a Direct Linear Transformation algorithm for 3D reconstruction, and 16 kinetic variables measured by a piezoelectric 3D force platform. Data were analyzed by Student's t-test and effect size statistics. Pearson correlations were applied to the data of the eighteen swimmers to relate the association of 53 kinematic, kinetic variables to the performance of the tumble-turn (3 meters Round Trip Time, 3m RTT). The approach and the whole turn times were faster for elite swimmers compared to sub elites (1.09±0.06 vs. 1.23±0.08 sec, and 2.89±0.07 vs. 3.15±0.11 sec.), as well as the horizontal speeds of the swimmers' head 1 m before the rotation (1.73±0.13 vs. 1.57±0.13 m/sec.), at the end of the push-off on force platform (2.55±0.15 vs. 2.31±0.22 m/sec.) and 3 m after the wall (2.01±0.19 vs. 1.68±0.12 m/sec.). Large differences (|d| > 0.8) in favor of the elite swimmers were identified for the index of upper body extension at the beginning of the push-off, the lower limb extension index at the end of push-off, and among the kinetic variables, the horizontal impulse and lateralization of the push-off. Correlations for the whole group revealed a moderate to strong relationship between 6 body extension indices and 3mRTT performance. For the kinetic variables, the correlations indicated the fastest swimmers in 3mRTT showed large lateral impulse during placement (r=0.46), maximum horizontal force during the push-off (r=0.45) and lateralization of the push-off (r=0.44) (all p<0.05). Elite female swimmers had higher approach and push-off speeds, were more streamlined through the contact, and showed a higher horizontal impulse and lateralization of the push-off, than their sub-elite counterparts.

Immunometabolism-fit: How exercise and training can modify T cell and macrophage metabolism in health and disease.

BACKGROUND: The term immunometabolism describes cellular and molecular metabolic processes that control the immune system and the associated immune responses. Acute exercise and regular physical activity have a substantial influence on the metabolism and the immune system, so that both processes are closely associated and influence each other bidirectionally. SCOPE OF REVIEW: We limit the review here to focus on metabolic phenotypes and metabolic plasticity of T cells and macrophages to describe the complex role of acute exercise stress and regular physical activity on these cell types. The metabolic and immunological consequences of the social problem of inactivity and how, conversely, an active lifestyle can break this vicious circle, are then described. Finally, these aspects are evaluated against the background of an aging society. MAJOR CONCLUSIONS: T cells and macrophages show high sensitivity to changes in their metabolic environment, which indirectly or directly affects their central functions. Physical activity and sedentary behaviour have an important influence on metabolic status, thereby modifying immune cell phenotypes and influencing immunological plasticity. A detailed understanding of the interactions between acute and chronic physical activity, sedentary behaviour, and the metabolic status of immune cells, can help to target the dysregulated immune system of people who live in a much too inactive society.

Acute respiratory illness and return to sport: a systematic review and meta-analysis by a subgroup of the IOC consensus on 'acute respiratory illness in the athlete'.

OBJECTIVE: To determine the days until return to sport (RTS) after acute respiratory illness (ARill), frequency of time loss after ARill resulting in >1 day lost from training/competition, and symptom duration (days) of ARill in athletes. DESIGN: Systematic review and meta-analysis. DATA SOURCES: PubMed, EBSCOhost, Web of Science, January 1990-July 2020. ELIGIBILITY CRITERIA: Original research articles published in English on athletes/military recruits (15-65 years) with symptoms/diagnosis of an ARill and reporting any of the following: days until RTS after ARill, frequency (%) of time loss >1 day after ARill or symptom duration (days) of ARill. RESULTS: 767 articles were identified; 54 were included (n=31 065 athletes). 4 studies reported days until RTS (range: 0-8.5 days). Frequency (%) of time loss >1 day after ARill was 20.4% (95% CI 15.3% to 25.4%). The mean symptom duration for all ARill was 7.1 days (95% CI 6.2 to 8.0). Results were similar between subgroups: pathological classification (acute respiratory infection (ARinf) vs undiagnosed ARill), anatomical classification (upper vs general ARill) or diagnostic method of ARinf (symptoms, physical examination, special investigations identifying pathogens). CONCLUSIONS: In 80% of ARill in athletes, no days were lost from training/competition. The mean duration of ARill symptoms in athletes was 7 days. Outcomes were not influenced by pathological or anatomical classification of ARill, or in ARinf diagnosed by various methods. Current data are limited, and future studies with standardised approaches to definitions, diagnostic methods and classifications of ARill are needed to obtain detailed clinical, laboratory and specific pathogen data to inform RTS. PROSPERO REGISTRATION NUMBER: CRD42020160479.

International Olympic Committee (IOC) consensus statement on acute respiratory illness in athletes part 2: non-infective acute respiratory illness.

Acute respiratory illness (ARill) is common and threatens the health of athletes. ARill in athletes forms a significant component of the work of Sport and Exercise Medicine (SEM) clinicians. The aim of this consensus is to provide the SEM clinician with an overview and practical clinical approach to non-infective ARill in athletes. The International Olympic Committee (IOC) Medical and Scientific Committee appointed an international consensus group to review ARill in athletes. Key areas of ARill in athletes were originally identified and six subgroups of the IOC Consensus group established to review the following aspects: (1) epidemiology/risk factors for ARill, (2) infective ARill, (3) non-infective ARill, (4) acute asthma/exercise-induced bronchoconstriction and related conditions, (5) effects of ARill on exercise/sports performance, medical complications/return-to-sport (RTS) and (6) acute nasal/laryngeal obstruction presenting as ARill. Following several reviews conducted by subgroups, the sections of the consensus documents were allocated to 'core' members for drafting and internal review. An advanced draft of the consensus document was discussed during a meeting of the main consensus core group, and final edits were completed prior to submission of the manuscript. This document (part 2) of this consensus focuses on respiratory conditions causing non-infective ARill in athletes. These include non-inflammatory obstructive nasal, laryngeal, tracheal or bronchial conditions or non-infective inflammatory conditions of the respiratory epithelium that affect the upper and/or lower airways, frequently as a continuum. The following aspects of more common as well as lesser-known non-infective ARill in athletes are reviewed: epidemiology, risk factors, pathology/pathophysiology, clinical presentation and diagnosis, management, prevention, medical considerations and risks of illness during exercise, effects of illness on exercise/sports performance and RTS guidelines.

International Olympic Committee (IOC) consensus statement on acute respiratory illness in athletes part 1: acute respiratory infections.

Acute illnesses affecting the respiratory tract are common and form a significant component of the work of Sport and Exercise Medicine (SEM) clinicians. Acute respiratory illness (ARill) can broadly be classified as non-infective ARill and acute respiratory infections (ARinf). The aim of this consensus is to provide the SEM clinician with an overview and practical clinical approach to ARinf in athletes. The International Olympic Committee (IOC) Medical and Scientific Commission appointed an international consensus group to review ARill (non-infective ARill and ARinf) in athletes. Six subgroups of the IOC Consensus group were initially established to review the following key areas of ARill in athletes: (1) epidemiology/risk factors for ARill, (2) ARinf, (3) non-infective ARill including ARill due to environmental exposure, (4) acute asthma and related conditions, (5) effects of ARill on exercise/sports performance, medical complications/return-to-sport and (6) acute nasal/vocal cord dysfunction presenting as ARill. Several systematic and narrative reviews were conducted by IOC consensus subgroups, and these then formed the basis of sections in the consensus documents. Drafting and internal review of sections were allocated to 'core' members of the consensus group, and an advanced draft of the consensus document was discussed during a meeting of the main consensus core group in Lausanne, Switzerland on 11 to 12 October 2021. Final edits were completed after the meeting. This consensus document (part 1) focusses on ARinf, which accounts for the majority of ARill in athletes. The first section of this consensus proposes a set of definitions and classifications of ARinf in athletes to standardise future data collection and reporting. The remainder of the consensus paper examines a wide range of clinical considerations related to ARinf in athletes: epidemiology, risk factors, pathology/pathophysiology, clinical presentation and diagnosis, management, prevention, medical considerations, risks of infection during exercise, effects of infection on exercise/sports performance and return-to-sport guidelines.

Identifying and analysing game styles and factors influencing a team's strategy in field hockey.

Characterising a team's game style is a performance analysis approach that captures game events, and groups them into profiles using clustering techniques to identify the consistent (and winning) strategies a team implements. The aim of this study was to identify the game styles of international hockey teams. Video footage from the 2019 Pro League tournament (n = 74 female and n = 57 male matches) were analysed retrospectively using a notational analysis system in SportsCode™. Variables were arranged into six game style categories (established attack game actions, counter attack game actions, established attack success, counter attack success, set pieces, tempo) and two game style types identified per category using a k-means clustering algorithm. Decision trees were used to identify the influence of extrinsic and intrinsic match factors on the probability of a team playing a particular game style. Opposition and other reference team game style categories were shown to be more important in predicting a game style category than contextual factors. Examination of team profiles highlights how different strategies are successful for different teams such as high-intensity attack or absorbing pressure and counter attacking. This performance analysis process provides practical insights into the holistic performance of international hockey teams.

"Train how you play": Using representative learning design to train amateur cricketers.

Training task design with amateur female cricketers has typically comprised of deconstructed and monotonous approaches which may not maximise skill development. Clear guidelines to improve these practices in this cohort are lacking. The training environment should provide the same sources of information, decisions and variability as matches in order to prepare players for the match environment, which can be achieved through representative learning design (RLD). An RLD training intervention designed to promote skill development was performed over five weeks with two amateur female cricket teams to provide a framework for community coaches at the foundation stage of cricket. Skill development was recorded as changes in skilled actions for batting and bowling, with cognitions coded as themes for each skill during training. Six of ten batters and seven of eight bowlers exhibited increases in skill development ranging between 7-49%. Changes in batting and bowling behaviour improved substantially between moderately and extensively designed sessions. Batters' thoughts shifted from their own skill execution to objectives, while bowlers focused on their opponent's execution. Moderate to extensive RLD appears to promote skill development in amateur cricketers, making it a viable option for coach education and training design at the foundation level of cricket.

Bayesian prediction of winning times for elite swimming events.

To develop a statistical model of winning times for international swimming events with the aim of predicting winning time distributions and the probability of winning for the 2020 and 2024 Olympic Games. The data set included first and third place times from all individual swimming events from the Olympics and World Championships from 1990 to 2019. We compared different model formulations fitted with Bayesian inference to obtain predictive distributions; comparisons were based on mean percentage error in out-of-sample predictions of Olympics and World Championships winning swim times from 2011 to 2019. The Bayesian time series regression model, comprising auto-regressive and moving average terms and other predictors, had the smallest mean prediction error of 0.57% (CI 0.46-0.74%). For context, using the respective previous Olympics or World Championships winning time resulted in a mean prediction error of 0.70% (CI 0.59-0.82%). The Olympics were on average 0.5% (CI 0.3-0.7%) faster than World Championships over the study period. The model computes the posterior predictive distribution, which allows coaches and athletes to evaluate the probability of winning given an individual's swim time, and the probability of being faster or slower than the previous winning time or even the world record.

Classification of Players Across the Australian Rules Football Participation Pathway Based on Physical Characteristics.

ABSTRACT: Haycraft, JAZ, Kovalchik, S, Pyne, DB, and Robertson, S. Classification of players across the Australian Rules football participation pathway based on physical characteristics. J Strength Cond Res 36(3): 702-709, 2022-This study investigated the utility of physical fitness and movement ability tests to differentiate and classify players into Australian Football League (AFL) participation pathway levels. Players (n = 293, age 10.9-19.1 years) completed the following tests; 5-m, 10-m, and 20-m sprint, AFL planned agility, vertical jump (VJ), running VJ, 20-m multistage fitness test (MSFT), and athletic ability assessment. A multivariate analysis of variance between AFL participation pathway levels was conducted, and a classification tree determined the extent to which players could be allocated to relevant levels. The magnitude of differences between physical fitness and movement ability were level-dependent, with the largest standardized effect size (ES) between Local U12, Local U14, and older levels for most physical fitness tests (ES: -4.64 to 5.02), except the 5-m and 10-m sprint. The 20-m, 5-m, AFL agility, 20-m MSFT, overhead squat, and running VJ (right) contributed to the classification model, with 57% overall accuracy reported (43% under cross-validation). National U16 players were easiest to classify (87%), while National U18 players were most difficult (0%). Physical fitness tests do not seem to differentiate between players after selection into AFL talent pathway levels. Other attributes (i.e., skill, psychological, and sociocultural) should be prioritized over physical fitness and movement attributes by selectors/coaches when considering selection of talented players.

Application of acute pre-exercise partial-body cryotherapy promotes jump performance, salivary α-amylase and athlete readiness.

This study aimed to evaluate the application of a single pre-exercise bout of partial-body cryotherapy (PBC) to augment jump performance, salivary biomarkers and self-reported performance readiness. Twelve male rugby union players (age 20.7 ± 3.2 yr; body mass 93.1 ± 13.9 kg; mean ± SD) were exposed to PBC for 3 min at -140°C or control condition prior to a pre-post series of loaded countermovement jumps (CMJ), salivary biomarker samples and performance readiness questionnaires. PBC elicited a moderately greater improvement in CMJ velocity of +4.7 ± 3.5% (mean ± 90% confidence limits) from baseline to 15 min in comparison with a -1.9 ± 4.8% mean difference in the control condition. The mean change in concentration of salivary α-amylase at 15 min was substantially increased by +131 ± 109% after PBC exposure, compared to a -4.2 ± 42% decrease in the control. Salivary testosterone concentrations were unclear at all timepoints in both the PBC and control interventions. Self-reported perceptions of overall performance readiness indicated small to moderate increases in mental fatigue, mood, muscle soreness and overall questionnaire score after PBC compared to control with a higher score more favourable for performance. The application of pre-exercise PBC can elicit favourable outcomes in controlled physical performance tests and holds promise to be applied to training or competition settings.

Training periodization for a world-class 400 meters individual medley swimmer.

We present a case study of the periodized training by a world-class 400-m Individual Medley (IM) swimmer (4th in 2019 World Championships) in the season leading to a bronze medal in the 2018 European Championship. The complexity of this IM preparation was based on the experiences, observations and innovations of an Olympic swimming coach. Over 52 weeks, a traditional periodization model was employed using three macrocycles. A total of 15 competitions were completed in the season increasing in frequency in the third macrocycle. The training intensity distribution (TID) followed the pattern of a traditional pyramidal model in general training and polarized and threshold models during specific training before competitions. Weekly training volume ranged from 25 to 79 km, 24 to 87 km, and 25 to 90 km in each of the three macrocyles. Altitude training comprised 23% of total training weeks. Haemoglobin [Hb] increased from 14.9 to 16.0 g/100 ml and haematocrit from 45.1 to 48.1% after altitude training. Heart rate (HR) and [La-] decreased at submaximal swimming intensities, while swimming velocity increased in the 8 × 100 m incremental swimming test in A2 (1.4%) and in AT (0.6%). Pull up power was increased 10% through the season.

The importance of previous season performance on world-class 200- and 400-m individual medley swimming.

We examined the degree to which 200-m and 400-m Individual Medley (IM) performance was related to sprint-, middle- and long-distance events before a swimmer reached a Top-20 world ranking. A retrospective longitudinal modelling study was conducted. Data on Top-20 swimmers between 2010 and 2018 were obtained from publicly available websites. A general linear model was used to examine associations between 200-m and 400-mIM performance (FINA ranking points) and performance in sprint, middle-distance and distance events in the previous two years. In the 200-mIM, there were significant associations (p < 0.001) between prior competition results obtained for both the 200-mIM (r = 0.80; ß = 0.543) and 400-m IM (r = 0.70; ß = 0.317) events before the Top-20 performance in 200-mIM in the year of the Top-20. Sprint distance events were associated (p < 0.006; r = 0.39; ß = 0.088) with 200-mIM (t). Each additional 10 FINA points in the 200-mIM in each of the two years preceding the Top-20 performance. were associated with an increase of 5 FINA points in 200-mIM in in the year of the Top-20 (goodness of fit R 2 = 0.70). There were similar associations (p < 0.001) for a Top 20-FINA 400-mIM performance with both 200-mIM (r = 0.72; ß = 0.385) and 400-m IM (r = 0.79; ß = 0.492) events in the two years before a swimmer reached the Top-20. Middle-distance events were associated with 400-mIM performance (p < 0.001; r = 0.53; ß = 0.163). Each additional 10 FINA points in 400-mIM in in each of the two years preceding the Top-20 performance were associated with an increase of 5 FINA points in in the year that a swimmer reached the Top-20 (goodness of fit R 2 = 0.75). The specificity and complexity of the IM require a thorough preparation in this event for world-class performances. The 200-mIM is more closely related to sprint distance events, whereas middle-distance events support preparations for the 400-mIM.

Ramadan intermittent fasting induced poorer training practices during the COVID-19 lockdown: A global cross-sectional study with 5529 athletes from 110 countries.

Ramadan intermittent fasting during the COVID-19 lockdown (RIFL) may present unique demands. We investigated training practices (i.e., training load and training times) of athletes, using pre-defined survey criteria/questions, during the 'first' COVID-19 lockdown, comparing RIFL to lockdown-alone (LD) in Muslim athletes. Specifically, a within-subject, survey-based study saw athletes (n = 5,529; from 110 countries/territories) training practices (comparing RIFL to LD) explored by comparative variables of: sex; age; continent; athlete classification (e.g., world-class); sport classification (e.g., endurance); athlete status (e.g., professional); and level of training knowledge and beliefs/attitudes (ranked as: good/moderate/poor). During RIFL (compared to LD), athlete perceptions (ranges presented given variety of comparative variables) of their training load decreased (46-62%), were maintained (31-48%) or increased (2-13%). Decreases (≥ 5%, p < 0.05) affected more athletes aged 30-39 years than those 18-29 years (60 vs 55%); more national than international athletes (59 vs 51%); more team sports than precision sports (59 vs 46%); more North American than European athletes (62 vs 53%); more semi-professional than professional athletes (60 vs 54%); more athletes who rated their beliefs/attitudes 'good' compared to 'poor' and 'moderate' (61 vs 54 and 53%, respectively); and more athletes with 'moderate' than 'poor' knowledge (58 vs 53%). During RIFL, athletes had different strategies for training times, with 13-29% training twice a day (i.e., afternoon and night), 12-26% at night only, and 18-36% in the afternoon only, with ranges depending on the comparative variables. Training loads and activities were altered negatively during RIFL compared to LD. It would be prudent for decision-makers responsible for RIFL athletes to develop programs to support athletes during such challenges.

Non-targeted metabolomics analyses by mass spectrometry to explore metabolic stress after six training weeks in high level swimmers.

The objective was to compare the metabolic responses of high-level national swimmers to threshold or polarised training. 22 swimmers (n = 12 males and 10 females) participated in a 28-week cross-over intervention study consisting of 2 × 6 period weeks of training. Swimmers were assigned randomly to either training group for the first period: polarised (POL) (81% in energetic zone 1: blood lactate [La]b ≤ 2 mmol.L-1; 4% in zone 2: 2 mmol.L-1 <[La]b ≤ 4 mmol.L-1; 15% in zone 3: [La]b > 4 mmol.L-1) or threshold (THR) (65%/25%/10%). Before and after each training period, urine samples were collected for non-targeted metabolomics analysis. Mixed model analysis was performed on metabolomics data including fatigue class factors and/or training and/or interaction. Ion intensities of 6-keto-decanoylcarnitine (+31%), pregnanediol-3-glucuronide (+81%), P-cresol sulphate (+18%) were higher in the threshold group (P < 0.05) indicating higher glycogenic depletion and inflammation without alteration of the neuroendocrine stress axis. 4-phenylbutanic acid sulphate was 200% higher in less fatigued swimmers (P < 0.01) linking the anti-inflammatory activity at the cell membrane level to the subjective perception of fatigue. This research suggests the importance of replenishing glycogen stores and reducing inflammation during high thresholds training loads.

Dietary Intake and Gastrointestinal Integrity in Runners Undertaking High-Intensity Exercise in the Heat.

Gastrointestinal disturbances are one of the most common issues for endurance athletes during training and competition in the heat. The relationship between typical dietary intake or nutritional interventions and perturbations in or maintenance of gut integrity is unclear. Twelve well-trained male endurance athletes (peak oxygen consumption = 61.4 ± 7.0 ml·kg-1·min-1) completed two trials in a randomized order in 35 °C (heat) and 21 °C (thermoneutral) conditions and kept a detailed nutritional diary for eight consecutive days between the two trials. The treadmill running trials consisted of 15 min at 60% peak oxygen consumption, 15 min at 75% peak oxygen consumption, followed by 8 × 1-min high-intensity efforts. Venous blood samples were taken at the baseline, at the end of each of the three exercise stages, and 1 hr postexercise to measure gut integrity and the permeability biomarker concentration for intestinal fatty-acid-binding protein, lipopolysaccharide, and lipopolysaccharide-binding protein. The runners self-reported gut symptoms 1 hr postexercise and 3 days postexercise. The heat condition induced large (45-370%) increases in intestinal fatty-acid-binding protein, lipopolysaccharide-binding protein, and lipopolysaccharide concentrations compared with the baseline, but induced mild gastrointestinal symptoms. Carbohydrate and polyunsaturated fat intake 24 hr preexercise were associated with less lipopolysaccharide translocation. Protein, carbohydrate, total fat, and polyunsaturated fat intake (8 days) were positively associated with the percentage increase of intestinal fatty-acid-binding protein in both conditions (range of correlations, 95% confidence interval = .62-.93 [.02, .98]). Typical nutrition intake partly explained increases in biomarkers and the attenuation of symptoms induced by moderate- and high-intensity exercise under both heat and thermoneutral conditions.