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Football academy settings may pose risks to adolescent athletes achieving sufficient sleep because of the contextual challenges these players face (e.g., psychosocial pressure, changes in training, competition, and academic stress). Given the importance of sleep to overall health as well as physical athletic development and injury risk, this study aimed to investigate whether differences in training schedules (morning vs. evening training sessions) affected objective measures of sleep in adolescent academy football (soccer) players. Twelve academy players (mean age 14.18 ± 1.36 years) wore an ActiGraph accelerometer on nights before, and nights of, training days in 2 separate weeks where morning (09:00-11:00 hours) and evening (18:00-20:00 hours) training occurred. Objective sleep parameters and training load data were collected. Night-time sleep periods were categorized as sleep preceding morning training, preceding evening training, or after evening training. One-way univariate and multivariate analyses of variance for repeated measures were performed to determine the impact of the training schedule on sleep. Significance levels were set at p < 0.05. The total sleep time was below the recommended guidelines (<8 hours) across conditions. A large significant effect of the training schedule on time attempted to fall asleep (p = 0.004, effect size [ES] = 0.40) and time of sleep (p = 0.003, ES = 0.41) was present, with post-evening sessions resulting in the latest times. Overall, the players' sleep behavior was resilient to changes in training schedules. However, the low sleep durations (and potential risks to physical performance/injury) suggest that sleep education coupled with practical interventions are required in this cohort. [ABSTRACT FROM AUTHOR]

Practitioners' perceptions regarding the use and effectiveness of research evidence in sport is not well understood. The purpose of the present study was to examine practitioners' perceptions around the use, implementation, and barriers to evidence-based practice (EBP) in sport science in the United States of America (USA). A survey (28 items) was completed by 67 full-time staff who were a physical performance team member employed by universities or professional sporting organizations in the USA. Questions included the use of research, contribution of research areas, barriers to accessing and implementing EBP, and methods of feedback to the coach and players. All respondents (100%) stated they used research evidence in their performance/training program, ranking research as contributing most (largest contribution = 1 to smallest contribution = 4) to individualized preparation or recovery recommendations (1.98 ± 1.02). The top 3 preferred sources of information were "peer-reviewed research" (100% of respondents), "conferences/seminars" (76%), and "practitioners within your sport" (63%). Commonly reported perceived barriers between accessing and implementing research were "lack of staff" (accessing = 33%, implementing = 46%) "time" (accessing = 38%, implementing = 48%) and nonapplicable research (accessing = 33%, implementing = 37%), whereas "poor player compliance" was a clear barrier to implementing EBP (56%). Practitioners most preferred, and actual, method of feedback for coaching staff (87% for both) and players (94 and 95%, respectively) was "informal conversations/speaking." Improved access to educational and financial resources, increased integration of staff in coach settings and understanding of player/coach contexts may help to alleviate barriers to EBP. [ABSTRACT FROM AUTHOR]

Blood-borne markers of fatigue such as creatine kinase (CK) and urea (U) are widely used to fine-tune training recommendations. However, predictive accuracy is low. A possible explanation for this dissatisfactory characteristic is the propensity of athletes to react to different patterns of fatigue indicators (e.g., predominantly muscular [CK] or metabolic [U]). The aim of the present trial was to explore this hypothesis by using repetitive fatigue-recovery cycles. A total of 22 elite junior swimmers and triathletes (18 ± 3 years) were monitored for 9 weeks throughout 2 training phases (low-intensity, high-volume [LIHV] and high-intensity, low-volume [HILV] phases). Blood samples were collected each Monday (recovered) and Friday (fatigued) morning. From measured values of CK, U, free-testosterone (FT), and cortisol (C) as determined in the rested and fatigued state, respectively, Monday-Friday differences (Δ) were calculated and classified by magnitude before calculation of ratios (ΔCK/ΔU and ΔFT/ΔC). Coefficient of variation (CV) was calculated as group-based estimates of reproducibility. Linear mixed modeling was used to differentiate inter- and intraindividual variability. Consistency of patterns was analyzed by comparing with threshold values (<0.9 or >1.1 for all weeks). Reproducibility was very low for fatigue-induced changes (CV ≥ 100%) with interindividual variation accounting for 45-60% of overall variability. Case-wise analysis indicated consistent ΔCK/ΔU patterns for 7 individuals in LIHV and 7 in HILV; 5 responded consistently throughout. For ΔFT/ΔC the number of consistent patterns was 2 in LIHV and 3 in HILV. These findings highlight the potential value of an individualized and multivariate approach in the assessment of fatigue. [ABSTRACT FROM AUTHOR]

Objective: Firefighter physical aptitude tests were administered to unskilled subjects and operational firefighters to evaluate the impact that testing bias associated with gender, age, activity-specific skills, or task familiarity may have upon establishing performance thresholds. Methods: These tests were administered in sequence, simulating hazmat incidents, ventilation fan carriage (stairs), motor-vehicle rescues, bushfire incidents, fire attacks, and a firefighter rescue. Participants included two unskilled samples (jV=14 and 22) and 143 firefighters. Results: Firefighter performance was not significantly different from the unskilled subjects. Participants from both genders passed the test, with scores unrelated to performance skill or age; however, familiarization significantly improved performance when the test was repeated. Conclusion: These outcomes confirmed this test to be gender-, age-, and skill-neutral. Familiarization effects could be removed through performing a single, pre-selection trial of the test battery. [ABSTRACT FROM AUTHOR]

Objective: This communication is the first of four describing the development of defensible firefighter-selection tests. The purpose was to identify a subset of essential, physically demanding tasks performed by contemporary urban firefighters. Methods: From existing procedural documentation and job analyses, 11 fire-station visits and interviews with 106 firefighters, and one focus-group meeting, 31 physically demanding tasks were identified and incorporated into a workforce survey. Using this tool, firefighters rated the importance, perceived difficulty, typical task durations, and annual performance frequency of each task. Results: Data from 989 respondents were analyzed, enabling a consolidation of these tasks into a subset of essential activities. Conclusions: These processes yielded a content-valid list of 15 essential, physically demanding tasks covering the full width of duties performed by urban firefighters from Australia’s largest fire and rescue organization. [ABSTRACT FROM AUTHOR]

Objective: In this third communication, the processes for converting criterion occupational tasks into bona fide pre-employment selection tests are presented using urban firefighters as the worked example. Methods: A total of 14 individuals participated in potential screening tests that targeted three loaded movement categories: single-sided load carriage (4 tests), dragging loads (2 tests), and overhead pushing and holding objects (5 tests). Results: Seven tests emerged, one performed as an isolated pass/fail barrier test (ladder raise) and six incorporated into a sequential, timed circuit simulating hazmat incidents, ventilation fan carriage (stairs), motor-vehicle rescues, bushfire incidents, fire attacks, and a firefighter rescue. Conclusion: Because three tests provided predicted performance speeds to replicate the oxygen cost of firefighters performing the corresponding occupational simulations, notional performance thresholds could be projected and recommended for the final phase of this research. [ABSTRACT FROM AUTHOR]

Objective: The physiological demands of 15 essential, physically demanding fire-fighting tasks were investigated to identify criterion tasks for bona fide recruit selection. Methods: A total of 51 operational firefighters participated in discrete, field-based occupational simulations, with physiological responses measured throughout. Results: The most stressful tasks were identified and classified according to dominant fitness attributes and movement patterns. Three movement classes (single-sided load carriage [5 tasks], dragging loads [4 tasks], and overhead pushing and holding objects [2 tasks]) and one mandatory strength task emerged. Seven criterion tasks were identified. Load holding and carriage dominated these movement patterns, yet no task accentuated whole-body endurance. Conclusion: Material handling movements from each classification must appear within a physical aptitude (selection) test for it to adequately represent the breadth of tasks performed by Australian urban firefighters. [ABSTRACT FROM AUTHOR]

Objective: The influence of variations in exercise mode, thermal state, and load carriage on cardiac and ventilatory predictors of metabolic rate were investigated. Methods: Fifteen males were studied at rest and during whole-, upper-, and lower-body exercise (unloaded and loaded) under thermoneutral and hot conditions. Results: Ventilatory predictions were superior in thermoneutral (residual mean square error range: 0.04 to 0.17 L•min vs 0.21 to 0.36 L•min) and hot conditions (0.03 to 0.07 L•min vs 0.21 to 0.24 L•min). Predictions derived from whole- or lower-body exercise, and unloaded or loaded exercise could be interchanged without significant error. Nevertheless, a mode-specific prediction was required for upper-body work, and mild hyperthermia significantly reduced the precision of cardiac predictions. Conclusion: Ventilatory predictions were more precise, but errors from heart-rate predictions could be minimized by using thermal-state and exercise mode-specific predictions. [ABSTRACT FROM AUTHOR]