Longitudinal Internal Training Load and Exposure in a High-Performance Basketball Academy.

ABSTRACT: Lever, JR, Duffield, R, Murray, A, Bartlett, JD, and Fullagar, HHK. Longitudinal internal training load and exposure in a high-performance basketball academy. J Strength Cond Res XX(X): 000-000, 2024-This study describes the longitudinal training exposure (session counts) and internal training load (Rating of Perceived Exertion [RPE] and Session Rating of Perceived Exertion [sRPE]) of youth basketball players at a high-performance academy, based on the training year, training term, and playing position. Historical internal training load and training exposure data were collated from 45 male high-performance youth basketball athletes between 2015 and 2019. Data included session duration, RPE, sRPE, training type, and date. Linear mixed models and pairwise comparisons were performed on the weekly means and categorized by training year (year 1, year 2, year 3), term (term 1, term 2, term 3, term 4), and playing position (Backcourt, Frontcourt). Linear mixed models indicate that the individual athlete had the greatest influence on variance in training load and exposure. Significant differences were observed for increased session count, duration, and sRPE (p < 0.001) in year 2 compared with year 1. These measures also increased within each year whereby term 3 and term 4 (p < 0.001) were significantly greater than term 1 and term 2. No significant differences were observed between playing position (p > 0.05). Training exposure and internal training load increase in year 2 from year 1 for high-performance youth basketball academy athletes. Differences between training load and exposure for terms (i.e., training blocks) suggest the phase of season influences training prescription, while playing position has limited effect.

Match Exposure, Consecutive Match Number, and Recovery Days Affect Match Running During International Women's Soccer Tournaments.

ABSTRACT: Brown, G, Massard, T, Wignell, T, McCall, A, and Duffield, R. Match exposure, consecutive match number, and recovery days affect match running during international women's soccer tournaments. J Strength Cond Res 38(3): 577-583, 2024-To determine the influence of tournament-specific factors (match exposure, consecutive matches, and days between matches) on match running in women's international soccer players (footballers), 28 players from 1 national team were observed over 4 international tournaments using 10 Hz global positioning system units. Linear mixed models with a forward selection approach were used to analyze the collective effect of tournament-specific factors of match exposure (playing time), consecutive matches (count), days between matches (count) and time on pitch on relative (min -1 ) match running metrics (total distance, high-speed running, very high-speed running, accelerations, and decelerations), and the change in these metrics between halves. The significance level was set at p < 0.05. Days between matches were included in the final models for total distance ( p < 0.0001), high-speed running ( p = 0.002), very high-speed running ( p = 0.025), and change in accelerations ( p < 0.0001) and decelerations ( p = 0.002). Prior match exposure was included in the models for total distance ( p = 0.021), change in total distance ( p < 0.0001), and change in high-speed running ( p = 0.0008). Consecutive match number was included in the model for deceleration ( p = 0.030), change in very high-speed running ( p = 0.016), change in acceleration ( p < 0.0001), and change in deceleration ( p < 0.0001). Time on pitch was included in the final total distance ( p = 0.044), high-speed running ( p < 0.0001), acceleration ( p < 0.0001), and deceleration ( p = 0.0003) models. Overall, reduced match running throughout tournaments was associated with increased time on pitch and ≤3 days between matches. Increasing match exposure and more time between matches minimizes reductions in match running between halves. Practitioners can use these variables to inform player monitoring during international soccer tournaments and on return to clubs.

Monitoring Training Load and Wellness of Female Footballers Transitioning Between Club and National Teams.

ABSTRACT: Brown, GA, Massard, T, Wignell, T, McCall, A, and Duffield, R. Monitoring training load and wellness of female footballers transitioning between club and national teams. J Strength Cond Res 37(11): 2235-2240, 2023-This study described the change in training and match internal loads, plus perceptual wellness during the transition between club and national teams (NTs) for female international footballers (soccer). Session count, session rating of perceived exertion (s-RPE), and perceptual wellness data were collected from 42 players from 1 NT between 2019 and 2021 for 7 NT tournaments. Data were collated into 7-day (1 week) microcycles to compare the 2 weeks before the first week of NT (transition in: NT-2, NT-1, NT1); and separately from the final NT week to the next 2 weeks in clubs (transition out: NTFinal, NT+1, NT+2). Data were analyzed using linear mixed-models, with session count, s-RPE or wellness as the outcome variable, week as the fixed effect, player name, and tournament as random effects. Tukey's adjusted post-hoc comparisons and Cohen's d effect sizes (ES) were compared between weeks. Significance level was set at p < 0.05. During the transition into NT, training and total session counts increased (p < 0.0001, ES > 0.67), training s-RPE increased (p = 0.012, ES = 0.35), whereas match count and s-RPE decreased (p < 0.05, ES < -0.34). During the transition out of NT, there were decreases in training session count (p < 0.05, ES < -0.37), match count, and total session count (p < 0.0001, ES < -0.86), and match and total s-RPE (p < 0.0001, ES < -0.63). Perceived wellness was not significantly different throughout (p > 0.05, ES = -0.34 to 0.35). Thus, training and match exposures differ between club and NTs, demonstrating these unique transitional periods require simple and effective load monitoring to inform training and recovery prescription when changing between club and NTs.

Intrinsic variables associated with low back pain and lumbar spine injury in fast bowlers in cricket: a systematic review.

BACKGROUND: Lumbar spine injuries in fast bowlers account for the greatest missed playing time in cricket. A range of extrinsic and intrinsic variables are hypothesised to be associated with low back pain and lumbar spine injury in fast bowlers, and an improved understanding of intrinsic variables is necessary as these may alter load tolerance and injury risk associated with fast bowling. This review critically evaluated studies reporting intrinsic variables associated with low back pain and lumbar spine injury in fast bowlers and identified areas for future investigation. METHODS: OVID Medline, EMBASE, SPORTDiscus, CINAHL, Web of Science and SCOPUS databases were last searched on 3 June 2022 to identify studies investigating intrinsic variables associated with low back pain and lumbar spine injury in cricket fast bowlers. Terms relevant to cricket fast bowling, and intrinsic variables associated with lumbar spine injury and low back pain in fast bowlers were searched. 1,503 abstracts were screened, and 118 full-text articles were appraised to determine whether they met inclusion criteria. Two authors independently screened search results and assessed risk of bias using a modified version of the Quality in Prognostic Studies tool. RESULTS: Twenty-five studies met the inclusion criteria. Overall, no included studies demonstrated a low risk of bias, two studies were identified as moderate risk, and twenty-three studies were identified as high risk. Conflicting results were reported amongst studies investigating associations of fast bowling kinematics and kinetics, trunk and lumbar anatomical features, anthropometric traits, age, and neuromuscular characteristics with low back pain and lumbar spine injury. CONCLUSION: Inconsistencies in results may be related to differences in study design, injury definitions, participant characteristics, measurement parameters, and statistical analyses. Low back pain and lumbar spine injury occurrence in fast bowlers remain high, and this may be due to an absence of low bias studies that have informed recommendations for their prevention. Future research should employ clearly defined injury outcomes, analyse continuous datasets, utilise models that better represent lumbar kinematics and kinetics during fast bowling, and better quantify previous injury, lumbar anatomical features and lumbar maturation. TRIAL REGISTRATION: Open Science Framework https://doi.org/10.17605/OSF.IO/ERKZ2 .

The type and extent of travel for professional footballers undertaking national team duties for a national football federation.

Elite football (soccer) involves club, continental and international fixtures, requiring players to undertake extensive travel [1]. For a national football federation, this includes the transport of players between club and camp/tournament commitments, which is often a point of contention between respective organisations [2]. Partly this contention results from the effects of travel, whereby jet lag and travel fatigue can negatively affect physical performance [3-5] and athlete wellbeing [6, 7]. Given the scarcity of data on elite players following travel, an initial step for any national football federation is to understand the volume and nature of travel undertaken by national team players. Such insight may better identify the schedule, timelines and needs of athletes' post travel. Better awareness of these travel needs can help maximise availability for training and minimise the impact of travel related stresses on performance or wellbeing. However, the regularity and volume of travel to national football team commitments has not previously been described. Further, travel demands are likely to vary significantly based on the location of the athlete and the national team camp. For countries outside of Europe, such as Australia, the travel demands and ensuing effects on player preparation can be substantial for both arrival into national team and on return to clubs [7]. Hence, detailed information regarding the type, frequency, and extent of travel for national team duties is important to aid in planning optimal travel schedules and interventions to assist players for international or club duty.

Protective guidelines and mitigation strategies for hot conditions in professional football: starting 11 Hot Tips for consideration.

Elevated heat, humidity and solar load combined with low air movement independently and additively impair performance, increase the perception of effort and the risk of heat-related illnesses. For the specific context of professional football, the Fédération Internationale de Football Association (FIFA) heat guidelines are often used as the default policy. Still, these seem less protective than guidelines in other sports or from countries traditionally exposed to extreme hot conditions. Following several high-profile international and continental competitions played in hot conditions (eg, 2014 FIFA World Cup Brazil), a series of cross-sectional studies showed that national team players and their managers unanimously mentioned that the hot and humid conditions during these matches made it difficult as a team to perform. Such a concern is likely to be relevant for the upcoming 2026 FIFA World Cup that will be held in the traditional June-July window across 16 host cities in Canada, Mexico and USA. Therefore, to better protect players' health and performance during training and match play in hot conditions, we present our starting 11 Hot Tips that should be considered and facilitated by governing bodies, competition organisers, clubs, staff members and players.

Where are We Headed? Evidence to Inform Future Football Heading Guidelines.

Given the scientific and public concern regarding the short-, medium- and long-term consequences of heading on brain health, being proactive about developing and implementing guidelines that help reduce the burden (volume, impact magnitude and injury risk) of heading in young and beginner players appears justified. This narrative review explores the evidence underpinning strategies that could be incorporated into future heading guidelines to reduce heading burden in players across all levels of football. A four-step search strategy was utilised to identify all data-based papers related to heading in football. Eligibility criteria for inclusion were: (1) original data, (2) study population included football players, (3) outcome measures included one or more of the following: number of headers, measurement of head acceleration during heading, or head/brain injury incidence, and (4) published in English or English translation available. In total, 58 papers were included that outlined strategies based on (1) game or team development, (2) player skill development and (3) equipment. In particular, greater emphasis existed for small-sided games (particularly in young players) where fewer headers are observed when compared with the conventional 11 versus 11 game, as well as reducing headers from goal kicks and corners. Evidence also existed for developing a heading coaching framework that focusses on technical proficiency as well as neuromuscular neck exercises integrated into general injury reduction exercise programs, enforcement of rules related to deliberate head contact and using lower-pressure match and training balls. To mitigate potential risks of heading on brain health, a number of pragmatic strategies have been examined in scientific studies and may be considered as part of future heading guidelines.

Flight Path and Scheduling Effects on Perceived Jet Lag, Fatigue, and Sleep in Footballers Traveling to and From National Teams.

PURPOSE: This study examined posttravel perceptual responses of national-team footballers (soccer) following different flight paths, arrival/departure times, and trip contexts. METHODS: Details of 396 flights from national-team players (N = 68) were obtained and verified via an online flight database. Each player provided ratings of perceptual fatigue, sleep, soreness, stress, and jet lag for 2 days before and after each trip. The flight path (continents of departure and arrival), travel context (into vs out of national team), and arrival and departure times were obtained for each trip. Linear mixed models compared the pretravel with posttravel change in perceptual responses based on flight path, context, and schedule. RESULTS: Perceived jet-lag ratings were more responsive to travel variables (R2 = .48) than other perceptual ratings (R2 < .26). Travel from Asia to Europe (P < .05) and Europe to Australia (P < .001) had significantly higher jet-lag ratings than all other paths. Fatigue scores were worst following Asia to Europe (P < .05) and Europe to Australia (P < .05) travel, while sleep scores were worst following Europe to Australia travel (P < .01). Perceptual responses were poorer following travel from national team to club compared with all other travel contexts (P < .05). Arrival during the daytime (11 AM to 5 PM) resulted in better perceptual responses than early-morning or late-night arrivals (P < .05). CONCLUSIONS: Perceived jet-lag ratings are more responsive to travel demands than perceptual wellness scales in national-team football athletes. Poorer perceptual responses may be expected when travel is longer in nature, ends later in the day, or involves travel out of the national team back to club.

The prevalence of relative age effects and the influence of the talent pool size on Australian male and female youth football.

The current study explored the association between talent pool size and relative age effects in Football Australia's talent pathway. It also compared relative age effects between male and female players. Participants were 54,207 youth football players (females: n = 12,527, age-range = 14.0-15.9; males: n = 41,680, age-range = 13.0-14.9) eligible for the National Youth Championships. We developed linear regression models to examine the association between the member federation size and the probability of a player being born earlier in the year. We also analysed selection probabilities based on birth quartile and year half across three layers. Overall, talent pool size was associated with a higher probability of selecting a player born in the first half of the year over the second. More specifically, an increase of 760 players led to a 1% higher selection probability for those born in the first six months of a chronological age group. In addition, there were more occurrences of relative age effects in the male than the female sample. Future studies should focus on the impact of the talent pool size on relative age effects at each major talent identification/selection stage of a talent pathway.

Travel Across More Time Zones Results in Worse Perceived Fatigue and Sleep in National-Team Footballers.

PURPOSE: This study investigated the association between (1) time zone difference and (2) travel direction (east vs west) with posttravel changes in perceptual responses of national-team footballers. METHODS: Travel schedules from 355 national-team trips (50 elite soccer players) were verified using an online flight database. All players provided perceptual ratings of fatigue, sleep quality, soreness, and stress to calculate changes in scores up to 2 days after travel. Trips were categorized as <3, 3 to 6, 6 to 9, or 9+ time zone changes, along with travel direction (eastward or westward). The pretravel to posttravel changes in perceptual ratings at days 1 and 2 postarrival were compared between time zone change and travel direction with linear mixed models. RESULTS: For every time zone crossed, poorer ratings of perceptual fatigue (ß = 0.068, P < .001), sleep (ß = 0.095, P < .001), soreness (ß = 0.0049, P < .001), and total wellness (ß = 0.214, P < .001) were observed. However, the models explained only small proportions of the variation in postflight perceptual responses (7%-18%). Regardless, travel across 9+ time zones resulted in significantly worse perceived fatigue, sleep, and total wellness for days 1 and 2 postarrival compared with travel with <6 time zones (P < .05). Additionally, fatigue, sleep, and total scores were worse on day 2 following trips of 9+ time zones. Eastward travel resulted in poorer sleep ratings (ß = 0.52, P < .001) than westward travel within time zone groupings. CONCLUSIONS: Perceptual ratings of fatigue and sleep become progressively worse as travel increases in national-team soccer players, especially after travel across 9+ time zones and eastward travel.

Effects of concurrent exercise training on body composition, systemic inflammation, and components of metabolic syndrome in inactive academics: a randomised controlled trial.

PURPOSE: Low physical activity in the academic workplace may increase the risk of cardiometabolic disease. This randomised controlled trial investigated the effect of 14 weeks of concurrent exercise training (CT) on components of metabolic syndrome, body composition, insulin resistance, and markers of systemic inflammation in inactive academics. METHODS: 59 inactive academics were randomised into a CT (n = 29) or wait-list control group (n = 30). CT performed supervised training at an onsite facility 3 times per week for 14 weeks and cardiometabolic health was assessed pre- and post-intervention. Aerobic capacity was measured via a metabolic cart. Dual-Energy X-ray Absorptiometry measured fat mass, lean mass, and central adiposity. Fasting blood samples were analysed for interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), Homeostatic Model Assessment for Insulin Resistance (HOMA-IR), glucose, and lipid profile. RESULTS: Following the intervention, there was a decrease in fat mass (mean ± SD; - 1.3 ± 1.4%), android fat mass (median (IQR); - 0.06 (0.27) kg), and visceral adipose tissue (median (IQR); - 66 (110) cm3) in CT, but not control. Lean mass (median (IQR); 1.35 (1.86) kg) and aerobic capacity (mean ± SD; 4.0 ± 3.1 mL/kg/min) increased in CT, but not in control. There were no changes in IL-6, TNF-a, HOMA-IR, glucose, or lipid profile in response to the intervention (P > 0.05). Changes in insulin resistance were positively associated with IL-6 in the control group only (coefficients [95%CI]; 5.957 [2.961, 8.953]). CONCLUSION: Implementing combined aerobic and resistance exercise training programs in academic institutions may be an appropriate intervention to increase physical activity and reduce risk factors associated with cardiometabolic disease. TRIAL REGISTRATION: The study was registered with the Australian New Zealand Clinical Trials Registry on the 23rd of April, 2019 (ACTRN12619000608167).

Determining Stroke and Movement Profiles in Competitive Tennis Match-Play From Wearable Sensor Accelerometry.

ABSTRACT: Perri, T, Reid, M, Murphy, A, Howle, K, and Duffield, R. Determining stroke and movement profiles in competitive tennis match-play from wearable sensor accelerometry. J Strength Cond Res 37(6): 1271-1276, 2023-This study determined stroke and movement accelerometry metrics from a wearable sensor and compared between court surface (grass vs. hard) and match outcome (win vs. loss) during competitive tennis match-play. Eight junior high-performance tennis players wore a trunk-mounted global positioning system, with in-built accelerometer, magnetometer, and gyroscope during singles matches on hard and grass courts. The manufacturer software calculated accelerometer-derived total player load (tPL). A prototype algorithm classified forehands, backhands, serves, and "other" strokes, thereby calculating stroke PL (sPL) from individual strokes. Movement PL (mPL) was calculated as the difference between tPL and sPL, with all metrics reported as absolute and relative (min -1 , %, and ·stroke). Analysis of accelerometer load and stroke count metrics was performed through a two-way (surface [grass vs. hard] × match outcome [win vs. loss]) analysis of variance ( p < 0.05) and effect sizes (Cohen's d ). No interaction effects for surface and match outcome existed for absolute tPL, mPL, and sPL ( p > 0.05). Increased mPL% featured on grass courts, whereas sPL% was increased on hard courts ( p = 0.04, d = 1.18[0.31-2.02]). Elevated sPL·min -1 existed on hard courts ( p = 0.04, d = 1.19[0.32-2.04]), but no differences in tPL·min -1 and mPL·min -1 were evident for surface or outcome ( p > 0.05). Relative forehand sPL (FH-sPL·min -1 ) was higher on hard courts ( p = 0.03, d = 1.18[0.31-2.02]) alongside higher forehand counts ( p = 0.01, d = 1.29[0.40-2.14]). Hitting demands are heightened on hard courts from increased sPL and counts. Conversely, increased mPL% on grass courts likely reflects the specific movement demands from point-play. Physical preparation strategies during training blocks can be tailored toward movement or hitting loads to suit competitive surfaces.

Differentiating Stroke and Movement Accelerometer Profiles to Improve Prescription of Tennis Training Drills.

ABSTRACT: Perri, T, Reid, M, Murphy, A, Howle, K, and Duffield, R. Differentiating stroke and movement accelerometer profiles to improve prescription of tennis training drills. J Strength Cond Res 37(3): 646-651, 2023-This study compared the movement- and stroke-related accelerometer profiles and stroke counts between common on-court tennis training drills. Ten, junior-elite, male tennis players wore a cervical-mounted global positioning systems, with in-built accelerometer, gyroscope, and magnetometer during hard court training sessions ( n = 189). Individual training drills were classified into 8 categories based on previous research descriptions. Manufacturer software calculated total player load (tPL), while a prototype algorithm detected forehand (FH), backhands (BH), and serves and then calculated a stroke player load (sPL) from individual strokes. Movement player load (mPL) was calculated as the difference between tPL and sPL. Drill categories were compared for relative ( . min -1 ) tPL, sPL, mPL, and stroke counts via a 1-way analysis of variance with effect sizes (Cohen's d ) and 95% confidence intervals. Highest tPL . min -1 existed in accuracy and recovery or defensive drills ( p < 0.05), with lowest tPL·min -1 values observed in match-play simulation ( p < 0.05). For sPL·min -1 , accuracy drills elicited greater values compared with all other drill types ( p < 0.05), partly via greater FH-sPL·min -1 ( p < 0.05), with lowest sPL·min -1 existing for match-play ( p < 0.05). Accuracy, open, and recovery or defensive drills result in greater BH-sPL·min -1 and BH . min -1 ( p < 0.05). Serve-sPL·min -1 is highest in technical and match-play drills ( p < 0.05). Higher mPL·min -1 existed in accuracy, recovery or defensive, 2v1 net, open, and 2v1 baseline ( p < 0.05). Furthermore, mPL·min -1 in points drills was greater than technical and match-play simulation drills ( p < 0.05). Higher hitting-based accelerometer loads (sPL·min -1 ) exist in accuracy drills, whereas technical and match-play drills show the lowest movement demands (mPL·min -1 ). These findings can aid individual drill prescription for targeting movement or hitting load.

Prototype Machine Learning Algorithms from Wearable Technology to Detect Tennis Stroke and Movement Actions.

This study evaluated the accuracy of tennis-specific stroke and movement event detection algorithms from a cervically mounted wearable sensor containing a triaxial accelerometer, gyroscope and magnetometer. Stroke and movement data from up to eight high-performance tennis players were captured in match-play and movement drills. Prototype algorithms classified stroke (i.e., forehand, backhand, serve) and movement (i.e., "Alert", "Dynamic", "Running", "Low Intensity") events. Manual coding evaluated stroke actions in three classes (i.e., forehand, backhand and serve), with additional descriptors of spin (e.g., slice). Movement data was classified according to the specific locomotion performed (e.g., lateral shuffling). The algorithm output for strokes were analysed against manual coding via absolute (n) and relative (%) error rates. Coded movements were grouped according to their frequency within the algorithm's four movement classifications. Highest stroke accuracy was evident for serves (98%), followed by groundstrokes (94%). Backhand slice events showed 74% accuracy, while volleys remained mostly undetected (41-44%). Tennis-specific footwork patterns were predominantly grouped as "Dynamic" (63% of total events), alongside successful linear "Running" classifications (74% of running events). Concurrent stroke and movement data from wearable sensors allows detailed and long-term monitoring of tennis training for coaches and players. Improvements in movement classification sensitivity using tennis-specific language appear warranted.

Inertial Sensor Estimation of Initial and Terminal Contact during In-Field Running.

Given the popularity of running-based sports and the rapid development of Micro-electromechanical systems (MEMS), portable wireless sensors can provide in-field monitoring and analysis of running gait parameters during exercise. This paper proposed an intelligent analysis system from wireless micro-Inertial Measurement Unit (IMU) data to estimate contact time (CT) and flight time (FT) during running based on gyroscope and accelerometer sensors in a single location (ankle). Furthermore, a pre-processing system that detected the running period was introduced to analyse and enhance CT and FT detection accuracy and reduce noise. Results showed pre-processing successfully detected the designated running periods to remove noise of non-running periods. Furthermore, accelerometer and gyroscope algorithms showed good consistency within 95% confidence interval, and average absolute error of 31.53 ms and 24.77 ms, respectively. In turn, the combined system obtained a consistency of 84-100% agreement within tolerance values of 50 ms and 30 ms, respectively. Interestingly, both accuracy and consistency showed a decreasing trend as speed increased (36% at high-speed fore-foot strike). Successful CT and FT detection and output validation with consistency checking algorithms make in-field measurement of running gait possible using ankle-worn IMU sensors. Accordingly, accurate IMU-based gait analysis from gyroscope and accelerometer information can inform future research on in-field gait analysis.

Fatigue and Recovery Time Course After Female Soccer Matches: A Systematic Review And Meta-analysis.

BACKGROUND: This study aimed to analyze the extent of fatigue responses after female soccer matches and the ensuing recovery time course of performance, physiological, and perceptual responses. METHODS: Three databases (PubMed, Web of Science, and SPORTDiscus) were searched in October 2020 and updated in November 2021. Studies were included when participants were female soccer players, regardless of their ability level. Further, the intervention was an official soccer match with performance, physiological, or perceptual parameters collected pre- and post-match (immediately, 12 h, 24 h, 48 h, or 72 h-post). RESULTS: A total of 26 studies (n = 465 players) were included for meta-analysis. Most performance parameters showed some immediate post-match reduction (effect size [ES] = - 0.72 to - 1.80), apart from countermovement jump (CMJ; ES = - 0.04). Reduced CMJ performance occurred at 12 h (ES = - 0.38) and 24 h (ES = - 0.42) and sprint at 48 h post-match (ES = - 0.75). Inflammatory and immunological parameters responded acutely with moderate-to-large increases (ES = 0.58-2.75) immediately post-match. Creatine kinase and lactate dehydrogenase alterations persisted at 72 h post-match (ES = 3.79 and 7.46, respectively). Small-to-moderate effects were observed for increased cortisol (ES = 0.75) and reduced testosterone/cortisol ratio (ES = -0.47) immediately post-match, while negligible to small effects existed for testosterone (ES = 0.14) and estradiol (ES = 0.34). Large effects were observed for perceptual variables, with increased fatigue (ES = 1.79) and reduced vigor (ES = - 0.97) at 12 h post-match, while muscle soreness was increased immediately post (ES = 1.63) and at 24 h post-match (ES = 1.00). CONCLUSIONS: Acute fatigue exists following female soccer matches, and the performance, physiological, and perceptual parameters showed distinctive recovery timelines. Importantly, physical performance was recovered at 72 h post-match, whereas muscle damage markers were still increased at this time point. These timelines should be considered when planning training and match schedules. However, some caution should be advised given the small number of studies available on this population. REGISTRATION: The protocol for this systematic review was pre-registered on the International Prospective Register of Systematic Reviews (PROSPERO, Registration Number: CRD42021237857).

Cooling strategies for firefighters: Effects on physiological, physical, and visuo-motor outcomes following fire-fighting tasks in the heat.

OBJECTIVES: Due to the nature of firefighting, most effective cooling interventions to reduce heat strain and optimise performance are not practically viable. This study quantified the effects of two practical cooling strategies, co-designed with subject-matter experts, on physiological strain and physical, perceptual, and visuo-motor performance during simulated firefighting in the heat. DESIGN: Randomised cross-over. METHODS: On three occasions 14 firefighters completed an 80-min simulation in a hot-humid environment (32.0[0.9]°C, 59[3]%RH) including two 20-min firefighting tasks in full protective clothing, each followed by 20-min seated recovery. Recovery involved removal of protective clothing and one of three interventions - control (CON; ambient-temperature water consumption), basic (BASIC; cool-water consumption, ambient-forearm immersion/towels, fan), and advanced (ADV; ice-slushy consumption, cool-forearm immersion/ice packs, misting-fan). Thermal (core temperature) and cardiovascular (heart rate, arterial pressure) responses were measured throughout, whilst physical (handgrip/balance), visuo-motor (reaction time/memory recall) and perceptual (fatigue/thermal sensation/comfort) measures were assessed pre- and post-trial. RESULTS: Compared to CON, core temperature was lower in BASIC and ADV following the second task (ADV: 37.7[0.4]; BASIC: 38.0[0.4]; CON: 38.3[0.4]°C) and recovery protocol (ADV: 37.5[0.3]; BASIC: 37.7 [0.3] CON: 38.3[0.4]°C). This was paralleled by lowered heart rate, rate pressure product, and thermal sensation following the recovery protocols, in the ADV and BASIC condition compared to CON (p < .05). No physical or visuo-motor outcomes differed significantly between conditions. CONCLUSION: Whilst these observations need to be extended to field conditions, our findings demonstrate that two novel cooling interventions developed in collaboration with subject-matter experts offered benefits for reducing thermal strain and optimising firefighter safety.

The exchange of health and performance information when transitioning from club to National football teams: A Delphi survey of National team practitioners.

OBJECTIVES: To establish agreement in National team contexts when players transition from club to National team about (i) what medical and physical information to collect, (ii) how to use information (iii) identifying challenges to collection and (iv) collection methods. DESIGN: Delphi survey. METHODS: A series of sequential online questionnaires were sent to heads of medical and performance of the 32 National teams following the FIFA 2018 World Cup. Two separate Delphi's; 'Medical' and 'Physical' were administered. The 'Medical' respondent was the person responsible for player health. 'Physical' referred to the person responsible for physical performance. Content analyses were performed, with subsequent rounds designed according to responses of the previous. Agreement was considered at ≥70%. RESULTS: Twenty-three Medical (72%) and 14 (44%) Physical heads participated in Round 1 (3 rounds total). Seventeen Medical and 12 Physical respondents completed all rounds. Medical information agreed upon injury epidemiology, screening and injury treatment strategies. Physical information included training/match-loads, fatigue, wellness and current exercise programmes. Both Medical and Physical agreed information should be used to plan and individualise player programmes. Additionally medical information should guide coaches' national team selection. Communication, willingness to share and quality/completeness of information were agreed as main challenges. Medical and Physical respondents agreed a standardised reporting form and electronic shared database as best option to collect information. CONCLUSIONS: Our findings highlight the importance of health and performance information exchange between national and club teams. Further, this exchange should be cooperative, symbiotic and a two-way process to assist with improving player health.

The relationship between team-level and league-level injury rate, type and location in a professional football league.

OBJECTIVES: To describe the relationship between team- and league-level variability of injury rate, type, and location over 6 seasons in professional Australian football (A-League). DESIGN: Prospective epidemiological study. METHODS: Injury incidence, type and location were collected from all A-League teams (n = 10) for 6 consecutive seasons (2012/13 to 2017/18) via a standardised injury surveillance system. Intra-class correlation and coefficient of variation were calculated to assess the between-season variability of injury measures for each team. To determine the relationship between team-level injury variability on league-level injury rates, Marginal Coefficient of Determination to Coefficient of Determination were then calculated from generalised linear mixed models. This allowed determination between season trends, where league-level injury incidence, type- and location rates as the response variables, season as the predictor variable and teams as random intercepts. RESULTS: The majority of teams showed poor to moderate correlations for between-season injury rates (intra-class correlation: r = 0.319-0.831), but also showed low-moderate variability between-seasons for injury rate (coefficient of variation 34 ±â€¯22%). League injury rates were stable, though were reduced in 2015/16 compared to 2012/13 (ß = 0.738; p = 0.011). Joint/Ligament injuries had coinciding significant reduction in 2015/16 (p = 0.001). The model variance showed the reduction of Joint/Ligament injuries was league-wide rather than team-specific (Marginal Coefficient of Determintion = 0.23; Coefficient of Determination = 0.23). CONCLUSIONS: In the A-League, low between-season injury rate variability from teams contributed to a stable league-level injury trend over seasons. A reduction in league injury rate in 2015/16 was mirrored by league-wide Joint/Ligament injury rates, without specific effect by team.

Validating an algorithm from a trunk-mounted wearable sensor for detecting stroke events in tennis.

This study analysed the accuracy of a prototype algorithm for tennis stroke detection from wearable technology. Strokes from junior-elite tennis players over 10 matches were analysed. Players wore a GPS unit containing an accelerometer, gyroscope and magnetometer. Manufacturer-developed algorithms determined stoke type and count (forehands, backhands, serves and other). Matches were video recorded to manually code ball contacts and shadow swing events for forehands, backhands and serves and further by stroke classifications (i.e., drive, volley, slice, end-range). Comparisons between algorithm and coding were analysed via ANOVA and Bland-Altman plots at the match-level and error rates for specific stroke-types. No significant differences existed for stroke count between the algorithm and manual coding (p > 0.05). Significant (p < 0.0001) overestimation of "Other" strokes were observed from the algorithm, with no difference in groundstrokes and serves (p > 0.05). Serves had the highest accuracy of all stroke types (≥98%). Forehand and backhand "drives" were the most accurate (>86%), with volleys mostly undetected (58-60%) and slices and end-range strokes likely misclassified (49-51%). The prototype algorithm accurately quantifies serves and forehand and backhand "drives" and serves. However, underestimations of shadow swings and overestimations of "other" strokes suggests strokes with reduced trunk rotation have poorer detection accuracy.