Aspire Academy

PurposeThe aim of this study was to confirm the impact of heat acclimation on aerobic performance in hot conditions and elucidate the transfer of heat adaptations to cool and hypoxic environments.MethodsTen males (VO2peak: 4.50 ± 0.50 L/min) completed two three-week interventions consisting of heat acclimation (HA: 36°C and 59% RH) and temperate training (TEMP: 18°C and 60% RH) in a counter-balanced crossover design. Training weeks consisted of four work-matched controlled heart rate sessions interspersed with one intermittent sprint session, and two rest days. Before and after the interventions VO2peak and 20-min time trial performance were evaluated in COOL (18°C), HOT (35°C) and hypoxic (HYP: 18°C and FiO2: 15.4%) conditions.ResultsFollowing HA, VO2peak increased significantly in HOT (0.24 L/min [0.01, 0.47], P = 0.040) but not COOL (P = 0.431) or HYP (P = 0.411), whereas TEMP had no influence on VO2peak (P ≥ 0.424). Mean time trial power output increased significantly in HOT (20 W [11, 28], P < 0.001) and COOL (12 W [4, 21], P = 0.004), but not HYP (7 W [−1, 16], P = 0.075) after HA, whereas TEMP had no influence on mean power output (P ≥ 0.110). Rectal (−0.13°C [−0.23, −0.03], P = 0.009) and skin (−0.7°C [−1.2, −0.3], P < 0.001) temperature were lower during the time trial in HOT after HA, whereas mean heart rate did not differ (P = 0.339).ConclusionsHA improved aerobic performance in HOT in conjunction with lower thermal strain and enhanced cardiovascular stability (similar heart rate for higher workload), whereas the mechanistic pathways improving performance in COOL and HYP remain unclear.

To develop age-specific reference intervals for physical performance test outcomes relevant to male youth Middle Eastern football players. We analyzed mixed-longitudinal data (observations range: 1751-1943 assessments) from a sample of 441 male youth outfield football players (chronological age range: 11.7-18.4y) as part of the Qatar Football Association and Aspire Academy development program over 14 competitive seasons. Semiparametric generalized additive models for location, scale, and shape estimated age-specific reference centiles for 10-m sprinting, 40-m sprinting, countermovement jump height, and maximal aerobic speed variables. The estimated reference intervals indicated that the distribution of the physical performance test scores increased monotonically and nonlinearly with advancing chronological age for sprinting and countermovement jump outcome measures, reaching a plateau after 16years common to each of these performance variables. The maximal aerobic speed median score increased substantially until ∼14.5years, with the nonlinear trend flattening off toward relatively older chronological ages. We developed age-related reference intervals for physical performance test outcomes relevant to youth Qatari football players. Country-wide age-specific reference intervals can assist in the longitudinal tracking of the individual players' progress over time against benchmark values derived from the reference population.

The youth-to-first team phase presents a number of challenges in the careers of modern football players with stagnation, inconsistent performance and dropout being reported. The aim of this study was to investigate the perception of staff involved in professional academy football clubs around the globe, with a particular focus on youth and first team transition demands, resources as well as transitions barriers and coping among male academy football players. Participants from 29 male youth academies distributed across 29 countries took part in the survey. Our main findings suggested training and match intensity reported as being greater at the senior-level and also pressure from parents. The majority of respondents indicated their clubs having long-term strategy for player development and specific roles supporting successful player transitions. Exposure to different playing styles was deemed important to prepare players for the first team. Likewise, having the academy and the first team training on the same site was perceived to ease the transition, with the majority of respondents indicating that players are able to cope with the pressure of first team training and games. Perceptions on whether staff do not have the skills/resources to prepare players for the changes in environment and culture when players move from youth-to-senior level were unclear. Collectively, our study extends previous transition research on youth football academies suggesting the importance of a club-based playing philosophy to prepare players for the first team demands and challenges.

The muscle perfusion response to postexercise cold-water immersion (CWI) is not well understood. We examined the effects of graded postexercise CWI upon global and regional quadriceps femoris muscle perfusion using positron emission tomography and [15O]H2O. Using a matched-group design, 30 healthy men performed cycle ergometer exercise at 70% V̇O2peak to a core body temperature of 38°C, followed by either 10 min of CWI at 8°C, 22°C, or seated rest (control). Quadriceps muscle perfusion; thigh and calf cutaneous vascular conductance; intestinal, muscle, and local skin temperatures; thermal comfort; mean arterial pressure; and heart rate were assessed at preexercise, postexercise, and after CWI. Global quadriceps perfusion was reduced beyond the predefined minimal clinically relevant threshold (0.75 mL per 100 g·min-1) in 22°C water versus control (difference (95% confidence interval (CI)), -2.5 (-3.9 to -1.1) mL per 100 g·min-1). Clinically relevant decreases in muscle perfusion were observed in the rectus femoris (-2.0 (-3.0 to -1.0) mL per 100 g·min-1) and vastus lateralis (-3.5 (-4.9 to -2.0) mL per 100 g·min-1) in 8°C water, and in the vastus lateralis (-3.3 (-4.8 to -1.9) mL per 100 g·min-1) in 22°C water versus control. The mean effects for vastus intermedius and vastus medialis perfusion were not clinically relevant. Clinically relevant decreases in thigh and calf cutaneous vascular conductance were observed in both cooling conditions. The present findings revealed that less noxious CWI (22°C) promoted clinically relevant postexercise decreases in global quadriceps muscle perfusion, whereas noxious cooling (8°C) elicited no effect.

To investigate the optimal pretaper duration on match running performance in a professional soccer team. The training load was monitored during daily training sessions and matches during 2 seasons according to different periodization strategies. Matches' running distances were collected using match analysis system. The data were analyzed in 3 types of mesocycle blocks of 5 (M5), 4 (M4), and 3 weeks (M3), concludes all of them by 1 taper week. Significant decreases in the training load during the taper weeks compared to standard weeks were observed in 3 types of mesocycle blocks (d ≥ 5; P < .01). An increase in overall match running performance was observed in matches played after the taper weeks compared to matches played after the standard weeks during M4 for all speed ranges (d ≥ 1.3; P < .05). The increase was only observed in low-intensity running (d = 1.3; P < .04) and total distance, low-intensity running, and intense running (d ≥ 1.3; P < .05) in M5 and M3, respectively. Match running performance following the taper weeks between the 3 different mesocycle durations was significantly higher in M4 for the number of high-speed running, sprinting, and high-intensity running (P < .05). The greatest enhancement of match running performance was observed at M4 when the training load was decreased by approximately 18% during the tapering period. This study suggests that a period of 3 standard weeks of training followed by 1 taper week is the optimal taper strategy when compared to different pretaper durations.

ObjectivesTo describe age group patterns for injury incidence, severity and burden in elite male youth football.MethodsProspective cohort study capturing data on individual exposure and time-loss injuries from training and matches over four seasons (2016/2017 through 2019/2020) at a national football academy (U13–U18; age range: 11–18 years). Injury incidence was calculated as the number of injuries per 1000 hours, injury severity as the median number of days lost and injury burden as the number of days lost per 1000 hours.ResultsWe included 301 players (591 player-seasons) and recorded 1111 time-loss injuries. Overall incidence was 12.0 per 1000 hours (95% CI 11.3 to 12.7) and burden was 255 days lost per 1000 hours (252 to 259). The mean incidence for overall injuries was higher in the older age groups (7.8 to 18.6 injuries per 1000 hours), while the greatest burden was observed in the U16 age group (425 days; 415 to 435). In older age groups, incidence and burden were higher for muscle injuries and lower for physis injuries. Incidence of joint sprains and bone stress injuries was greatest for players in the U16, U17 and U18 age groups, with the largest burden observed for U16 players. No clear age group trend was observed for fractures.ConclusionInjury patterns differed with age; tailoring prevention programmes may be possible.

ObjectivesTo describe the injury characteristics of male youth athletes exposed to year-round athletics programmes.MethodsInjury surveillance data were prospectively collected by medical staff in a cohort of youth athletics athletes participating in a full-time sports academy from 2014–2015 to 2018–2019. Time-loss injuries (>1 day) were recorded following consensus procedures for athletics. Athletes were clustered into five event groups (sprints, jumps, endurance, throws and non-specialised) and the number of completed training and competition sessions (athletics exposures (AE)) were calculated for each athlete per completed season (one athlete season). Injury characteristics were reported overall and by event groups as injury incidence (injuries per 1000 AE) and injury burden (days lost per 1000 AE).ResultsOne-hundred and seventy-eight boys (14.9±1.8 years old) completed 391 athlete seasons, sustaining 290 injuries. The overall incidence was 4.0 injuries per 1000 AE and the overall burden was 79.1 days lost per 1000 AE. The thigh was the most common injury location (19%). Muscle strains (0.7 injuries per 1000 AE) and bone stress injuries (0.5 injuries per 1000 AE) presented the highest incidence and stress fractures the highest burden (17.6 days lost per 1000 AE). The most burdensome injury types by event group were: bone stress injuries for endurance, hamstring strains for sprints, stress fractures for jumps, lesion of meniscus/cartilage for throws and growth plate injuries for non-specialised athletes.ConclusionAcute muscle strains, stress fractures and bone stress injuries were identified as the main injury concerns in this cohort of young male athletics athletes. The injury characteristics differed between event groups.

The primary aim of the present study was to analyze mechanical responses during inertial knee- and hip-dominant hamstring strengthening exercises (flywheel leg-curl and hip-extension in conic-pulley), and the secondary aim was to measure and compare regional muscle use using functional magnetic resonance imaging. Mean power, peak power, mean velocity, peak velocity and time in the concentric (CON) and eccentric (ECC) phases were measured. The transverse relaxation time (T2) shift from pre- to post-exercise were calculated for the biceps femoris long (BFl) and short (BFs) heads, semitendinosus (ST) and semimembranosus (SM) muscles at proximal, middle and distal areas of the muscle length. Peak and mean power in flywheel leg-curl were higher during the CON than the ECC phase (p<0.01). ECC peak power was higher than CON phase (p<0.01) in conic-pulley hip-extension exercise, while mean power was higher during the CON than ECC phase (p<0.01). Flywheel leg-curl showed a higher T2 values in ST and BFs and BFl (p<0.05), while the conic-pulley hip-extension had a higher T2 values in the proximal region of the ST and BFl (p<0.05). In conclusion, ECC overload was only observed in peak power during the conic-pulley hip-extension exercise. Flywheel leg-curl involved a greater overall use of the 4 muscle bellies, more specifically in the ST and BFs, with a selective augmented activity (compared with the conic-pulley) in the 3 regions of the BFs, while conic-pulley hip-extension exercise selectively targeted the proximal and medial regions of the BFl. Physiotherapists and strength and conditioning coaches should consider this when optimizing the training and recovery process for hamstring muscles, especially after injury.

PurposeWe determined the effect of custom foot orthotics manufactured from ethyl-vinyl acetate (EVA) and expanded thermoplastic polyurethane (TPU) materials, both compared to a control condition (CON; shoes only) during repeated sprints on running mechanical alterations.MethodsEighteen males performed eight, 5-s sprints with 25-s recovery on an instrumented sprint treadmill in three footwear conditions (EVA, TPU and CON). Mechanical data consisted of continuous (step-by-step) measurement of running kinetics and kinematics, which were averaged for each sprint for further analysis.ResultsDistance ran in 5 s decreased from first to last sprint (P < 0.001), yet with higher sprints 1–8 values for both EVA (P = 0.004) and TPU (P = 0.018) versus CON. Regardless of footwear condition, mean horizontal forces, step frequency, vertical and leg stiffness decreased from sprint 1 to sprint 8 (all P < 0.001). Duration of the propulsive phase was globally shorter for both EVA (P = 0.002) and TPU (P = 0.021) versus CON, while braking phase duration was similar (P = 0.919). In the horizontal direction, peak propulsive (P < 0.001), but not braking (P = 0.172), forces also decreased from sprint 1 to sprint 8, independently of conditions.ConclusionCompared to shoe only, wearing EVA or TPU custom foot orthotics improved repeated treadmill sprint ability, yet provided similar fatigue-induced changes in mechanical outcomes.

The purpose of the study was to examine the differences in bilateral deficit (BLD) at different loadings during the half-squat jump (SJ) and horizontal countermovement jump (HCMJ) to determine if there is a relationship with linear sprint or change of direction (COD). The second goal was to check if fast players were more powerful in SJ and HCMJ than slow players in bilateral performance (BP). Twenty-seven male youth soccer players participated in the study. Players were divided in two groups, faster and slower, according to their sprint performance (10 and 40 m). BLD average power with body weight (BW) and 25%BW were significantly higher than 50%BW (p < 0.01). BLD during HCMJ was significantly higher than BLD during SJ with BW, 25%BW and 50%BW (p < 0.01). There were no statistical relationships between BLD and sprint or COD performance (p > 0.05). Fast players showed significantly higher SJ power with all the different loads and HCMJ than slow players (p < 0.01), and fast players lost more time executing COD-90° than slow players (p < 0.01). There were no statistical differences between fast and slow players in BLD. BLD seems to be dependent on motor task, contraction type and load and could not be a proper measure to estimate sprint and COD performance. Faster players are confirmed to be more powerful players than slow players, and decrements in COD could be a key benchmark to identify deficit between linear and COD performance.