CHANGES IN BACK SQUAT BAR VELOCITY AND PERCEIVED MUSCLE SORENESS FOLLOWING A STANDARDISED RUGBY LEAGUE MATCH SIMULATION

This study examined changes in back squat bar velocity and perceived muscle soreness following a rugby league match simulation protocol. Twenty male rugby league players (age: 19.8 ± 0.7 yrs) were recruited for this study. Back squat bar velocity and perceived muscle soreness of the lower body were collected on four days surrounding a match simulation: -24 h (prior to match simulation), +0 h (after the match simulation), +24 h and +48 h. Compared to baseline (-24h), there were non-significant decreases in maximum (dz=-0.50, moderate) back squat bar velocity +0 h. There was a significant increase in perceived muscle soreness at +0h only (p=0.003). Results suggest that elevated muscle soreness may not indicate impaired neuromuscular performance and highlight the importance of monitoring fatigue via multiple measures to ensure appropriate coaching decisions are made

MEASURING INSTANTANEOUS VELOCITY IN FOUR SWIM STROKES USING AN AUTOMATIC HEAD TRACKING SYSTEM: A COMPARISON STUDY

This study compared instantaneous swimming velocity from an automated video-based system to a tethered speedometer. Twenty-two state- and national-level swimmers (7 M, 15 F; 14.5 ± 2.5 yrs) swam 25 m of each stroke at maximal intensity. Bland-Altman plots showed good agreement between systems for backstroke and freestyle but poorer agreement for butterfly and breaststroke. The RMS error was also lower in backstroke and freestyle compared to butterfly and breaststroke. The differences in systems may be explained by the different body segments tracked by each system (head vs hips) and with differences being more apparent during butterfly and breaststroke due to the wave-like motion of these strokes. While the automated video-based system is suitable for measuring instantaneous swimming velocity, coaches, sports scientists, and swimmers should be aware of larger discrepancies between systems when assessing butterfly and breaststroke

Analysis of Training Loads in Elite Under 18 Australian Rule Football Players

Elsworthy, N ORCiD: 0000-0002-5223-6803Differences in training loads (TL) between under 18 (U18) Australian Rules football (AF) State Academy selected and non-selected players were investigated. Players were categorised relating to their highest representative level; State Academy selected (n = 9) and TAC Cup level players (n = 38). Data were obtained from an online training-monitoring tool implemented to collect player training and match information across a 20 - week period during the regular season. Parameters modelled included AF skills, strength, and other sport training sessions. Descriptive statistics (mean ± SD) and between-group comparisons (Cohen's d) were computed. A J48 decision tree modelled which TL variables could predict selection level. Pooled data showed 60% of weekly training duration consisted of AF training sessions. Similar AF TL were reported between State Academy and TAC Cup players (1578 ± 1264 arbitrary units (AU) v 1368 ± 872 AU; d = .05). While higher TL were reported for State selected players comparative to TAC Cup in total training (d = .20), core stability (d = .36), flexibility (d = .44), on-feet conditioning (d = .26), and off-feet conditioning (d = .26). Decision tree analysis showed core stability duration and flexibility TL the most influential parameters in classifying group selection (97.7% accuracy TAC Cup level; 35.8% accuracy State Academy level). Insights of U18 AF players' weekly training structures, loads, and characteristics of higher achieving players are provided. This study supports the application of training diaries and session rating of perceived exertion (sRPE) for TL monitoring in junior athletes

Within Game and Between Gender Comparisons of Match Demands in Men’s and Women’s International Touch Rugby World Cup

Touch rugby is an intermittent, high-intensity, anaerobic team sport that is widely played internationally as the Federation of International Touch includes 47-member nations. PURPOSE: The present study quantified and compared the match demands of men’s and women’s international touch rugby players during the 2019 world cup. METHODS: Match demands (male: n=16; female: n=15) were assessed via 5Hz global positioning system devices. Separate linear mixed models and Cohen’s effect size comparisons were used to compare variables within matches (1st v 2nd half) for men’s and women’s only matches, while between gender comparisons were made for complete match demands. RESULTS: Within match comparisons revealed significant, small reductions in running distance (p = 0.003) and one-minute peak average speed (p = 0.019) for men’s matches in the second half compared to the first half. For women’s matches a significant, small reduction in running distance (p \u3c0.001) and a significant, small increase for walking distance (p \u3c0.001) was revealed during the second half compared to the first half. Significant, small to moderate differences were found between men’s and women’s matches for average speed (p = 0.006), running distance (p \u3c0.001), sprint distance (p \u3c0.001), and peak speed (p \u3c0.001). CONCLUSION: Findings show the physical demands of men’s touch rugby matches are more demanding than women’s matches. Results from our study suggest that gender specific conditioning programs should be implemented to ensure suitable preparation for international matches

Player chronotype does not affect shooting accuracy at different times of the day in a professional, male basketball team: a pilot study

Athlete chronotype has been documented to underpin diurnal variations in skill execution across various team sports. However, no research has explored the effects of athlete chronotype on basketball-specific skills at different times of the day. Therefore, the aim of this study was to explore diurnal variations in basketball shooting accuracy according to chronotype. Professional, male basketball players (n = 13) completed a Morningness- Eveningness Questionnaire and were categorised into chronotypes using a tertile split technique (morning-types: n = 4; neither-types: n = 4; evening-types: n = 5). Players completed separate trials of a shooting accuracy test in the morning (08:00-09:30h) and afternoon (15:00-16:30h) with each trial consisting of 20 shots attempted from four court locations at either two- or three-point distances and one-shot location from the free-throw line (100 shots in total). Each shot attempt was scored using a 0-3-point scale with higher scores awarded to more accurate shots. Non-significant (p >0.05) differences in shooting scores were evident between morning and afternoon trials for each chronotype group, with small-large effects in shooting scores favouring the morning across groups. Moreover, non-significant (p >0.05) differences in shooting scores were apparent between chronotype groups in the morning (small-large effects) and afternoon (moderate-large effects). Shooting accuracy appears to remain consistent across morning and afternoon performances irrespective of player chronotype in a professional basketball team, suggesting coaches may not need to schedule training sessions involving shooting tasks at specific times of the day to optimise shooting accuracy in players

Factors influencing the physiological and perceptual decision-making demands of Australian football field umpires

Research Doctorate - Doctor of Philosophy (PhD)Team sport officials are an essential component of sport to ensure a fair and safe competition by enforcing the laws of the game. Some team sport officials (including but not limited to Australian football, soccer, rugby league and rugby union) have been referred to as “interactor” officials (MacMahon et al., 2014). Interactors are suggested to have “high interaction and physical movement demands and often a large number of cues to process” (MacMahon et al., 2014). These interactor officials are often exposed to extensive physical demands to maintain an ideal position around play to make perceptual judgements, based upon the actions of the players. Both the physical and perceptual decision-making tasks are performed simultaneously in order to apply the laws of the game. Despite this dual-task requirement of match play, the physical and perceptual decision-making training methods are typically applied in isolation, which fails to provide ecologically valid training strategies. Therefore, the overall aim of this thesis was to observe the physical and perceptual decision-making demands of match play and examine the effects of combined training methods in order to best replicate the match environment. An examination of the specific match demands of elite Australian football (AF) umpires has remained relatively unknown. In particular, no data have detailed the free kick decision-making performance of an umpire during match play, despite this being considered his/her primary role. Of further interest, the physical demands of different field umpire positions (mid-zone or end-zone) are yet to be examined. Therefore, to quantify the overall match demands of AF umpiring, 29 elite AF field umpires (age: 32.4 ± 6.1 yr; height: 181.7 ± 5.7 cm; body mass: 73.6 ± 5.4 kg) were assessed during 20 Australian Football League (AFL) matches (Study 1). Time-motion analysis data was collected from 5 Hz MinimaxX global positioning system (GPS) devices, and free kick decision-making accuracy was assessed by elite umpire coaches following each match. It was shown that field umpires covered a total distance (TD) of 10,563 ± 608 m, of which high speed running (HSR; > 14.4 km·h⁻¹) comprised 1,952 ± 494 m. Significant reductions (p < 0.05) were reported in both the TD and HSR distance following the first quarter. Significantly greater (p < 0.05) HSR and relative distances were covered within the mid-zone, compared to the end-zone demands. Overall, 44 ± 8 free kicks were awarded throughout a match, at an accuracy of 84 ± 6%. The number of free kicks awarded and decision-making accuracy (% correct) were consistent (p > 0.05) across quarters. Separately, the results show that despite reductions in the physical demands following the first quarter, decision-making accuracy is maintained throughout a match. Therefore decision-making performance was not directly compromised by the intermittent running demands that were completed by the AF umpires. The reduced physical demands of the end-zone (compared to the mid-zone) position allow for some physical recovery between bouts within the mid-zone, and these rotations permit the match demands are shared amongst all umpires. As such, the results of Study 1 provide current information regarding the physical and perceptual decision-making requirements of elite field umpires within AFL match play. In addition to Study 1, there is limited data available on sub-elite AFL umpires and comparison of the demands of elite and sub-elite AF umpires is important to compare the performance characteristics between the two levels of competition. Sub-elite AF competitions are vital for the development of umpire skills in their progression towards officiating elite match play. It is however unknown if these matches adequately prepare sub-elite umpires for the requirements of elite competition. Study 2 aimed to compare the physical and decision-making demands of elite and sub-elite competition. During 27 matches, time-motion analysis and free kick decision-making performance as described in Study 1 were examined for 36 AF umpires (elite: n = 29, age: 32.4 ± 6.1 yr, height: 181.7 ± 5.7 cm, body mass: 73.6 ± 5.4 kg; sub-elite: n = 7, age: 23.2 ± 2.3 yr, height: 178.2 ± 11.3 cm, body mass: 70.9 ± 7.3 kg). Significant differences (p < 0.05) in the TD and HSR existed between groups, with sub-elite umpires completing greater physical demands compared to elite umpires. Alternatively, elite umpires were superior in their free kick decision-making. Specifically, the number of correct decisions was similar, however sub-elite umpires made more incorrect decisions (16 errors; 68% correct) when compared to elite umpires (7 errors; 84% correct). The main findings of Study 2 highlight that the physical demands of sub-elite umpires are greater, which may contribute to them exhibiting poorer decision-making. These differences are likely due to a combination of factors including positioning, anticipation, rule knowledge and interpretation. Coaching staff need to ensure that they continue to develop the perceptual decision-making skills of sub-elite umpires to prepare them for elite match play performance. While Study 1 and Study 2 details the overall physical and perceptual decision-making demands of elite and sub-elite umpires, the physical aspects of their performance may present a number of potential factors limiting their perceptual decision-making abilities. As such, Study 3 investigated the effects of positioning and retrospective physical demands on the free kick decision-making accuracy of elite AF umpires. Using the same data that was analysed in Study 1, this study investigated how the positioning and physical demands may influence the free kick decision-making accuracy of elite AF umpires. It was shown that most decisions were made from a distance of 11-15 m from play; however distance from play had no significant effect on free kick decision-making accuracy (p > 0.05). In addition, the movement speed at the time of a decision had no effect on decision-making (p > 0.05). However, the running speed immediately prior to incorrect decisions was significantly higher (p < 0.05) than for correct decisions. These findings demonstrate that while there is no effect of distance from play or instantaneous velocity on decision-making accuracy, a higher running speed prior to a decision increases the likelihood of a decisional error. As such, superior anticipatory skills that would reduce the running demands prior to a decision may improve the decision-making accuracy of umpires. Despite the knowledge of the physical and physiological demands of interactor sports officials, little is known as to the relationship of these demands with decision-making performance, in particular during intermittent exercise typical of field-based team sport competition. Numerous laboratory-based studies have suggested that upon the onset of exercise, psychomotor performance continues to improve during steady state and incremental exercise before decreasing at higher exercise intensities, yet limited data is available for intermittent exercise. As such, the purpose of Study 4 was to examine changes in psychomotor performance of interactor sports officials during a laboratory based match simulation. Twelve elite interactor sports officials (age: 32.5 ± 5.5 yr; height: 180.0 ± 6.8 cm; body mass: 78.8 ± 7.6 kg) completed an intermittent match simulation on a non-motorised treadmill, while repeatedly completing a psychomotor task (Eriksen Flanker). Significant reductions (p < 0.05) in physical performance measures were observed towards the end of the simulation, however psychomotor performance was maintained throughout. However, when undertaking HSR (> 65% of maximal sprinting speed [MSS]), there was a significant improvement (p < 0.05) in psychomotor performance when compared with lower running speeds (< 65% MSS). Collectively, it appears that interactor sports officials can maintain their psychomotor performance through a laboratory simulation, despite reductions in the physical performance measures. Further, short duration bouts of HSR may actually promote psychomotor performance during intermittent exercise; possibly due to changes in central nervous system (CNS) arousal and cerebral blood flow (CBF) as a result of the increased running speed. Finally, the aim of Study 5 was to examine the effects of a combined high-intensity interval training (HIIT) and psychomotor training program on performance during an intermittent laboratory protocol. Ten sub-elite interactor sports officials (age: 22.5 ± 4.1 yr; height: 181.8 ± 8.3 cm; body mass: 75.7 ± 9.7 kg) initially completed a match simulation on the non-motorised treadmill (similar to that used in Study 4). Based on individual psychomotor performance, participants were placed either in a psychomotor training (n = 5) or physical conditioning (n = 5) group. Both groups completed a 6-week HIIT program (2 sessions per week; 4 sets of 3 or 4 min running efforts @ 90-95% maximum heart rate), with the psychomotor training group completing additional psychomotor training during the 3 min inter-interval recovery periods. Significant improvements (p < 0.05) were identified in maximal oxygen consumption (V̇O₂max) and velocity at V̇O₂max for both groups. Magnitude-based inferences suggest that the combined psychomotor and physical conditioning program provided a beneficial effect on psychomotor performance during and following the match simulation. The outcomes of the current study present a framework for the application of replicating the match environment for the acquisition of psychomotor skill of interactor sport officials. Collectively, these findings demonstrate the extensive physical and perceptual decision-making demands of AF umpires during match play. A considerable gap exists between elite and sub-elite umpires free kick decision-making accuracy thus highlighting the importance of developing decision-making performance through training. Further, traditional training methods used within interactor sports officials typically isolate the physical and decision-making aspects and as a result, they do not replicate the match demands. Overall, the findings of this thesis highlight the physical and decision-making demands of interactor sports officials, and provides a potential framework for the development of training strategies in order to replicate the physical and perceptual decision-making demands of match play

The match demands of Australian Rules Football umpires in a state-based competition

Purpose: The main purpose of the present study was to quantify the match running demands and physiological intensities of AF field and boundary umpires during match play. Methods: Thirty-five AF umpires [20 field (age: 243 +/- 7.7 y, body mass: 74.3 +/- 7.1 kg, Sigma 7 skinfolds: 67.8 +/- 18.8 mm); 15 boundary (age: 29.6 +/- 13.6 y, body mass: 71.9 +/- 3.1 kg, Sigma 7 skinfolds: 65.6 +/- 8.8 mm)] volunteered to participate in the study. Movement characteristics [total distance (TD), average running speed, high-intensity activity (HIA; >14.4 km.h(-1)) distance] and physiological measures [heart rate, blood lactate concentration ([BLa-]), and rating of perceived exertion] were collected during 20 state-based AF matches. Results: The mean (+/- SD) TD covered by field umpires was 11,492 +/- 1,729 m, with boundary umpires covering 15,061 +/- 1,749 m. The average running speed in field umpires was 103 +/- 14 m.min(-1) and was 134 +/- 14 m.min(-1) in boundary umpires. Field and boundary umpires covered 3,095 +/- 752 m and 5,875 +/- 1,590 m, during HIA, respectively. In the first quarter, HIA distance (field: P = .004, eta(2) = 0.071, boundary: P < .001, eta(2) = 0.180) and average running speed (field: P = .002, eta(2) = 0.078, boundary: P < .001, eta(2) = 0.191) were significantly greater than in subsequent quarters. Conclusions: The results demonstrate that both AF field and boundary umpires complete similar running demands to elite AF players and are subject to physical fatigue. Further research is warranted to see if this physical fatigue impacts on the cognitive function of AF umpires during match play

Physical and psychomotor performance of Australian football and rugby league officials during a match simulation

The onset of exercise facilitates an improvement in psychomotor performance until the second ventilatory threshold, after which performance is reduced. This inverted-U relationship appears valid for incremental and steady-state exercise, however, not for intermittent exercise. This study examined changes in psychomotor performance of team sport officials during a laboratory-based match simulation. Twelve elite Australian football (n = 5) and rugby league (n = 7) officials (32.5 ± 5.5 years; 180.0 ± 6.8 cm; 78.8 ± 7.6 kg) completed the match simulation on a non-motorised treadmill. Physiological measures were routinely taken, while psychomotor performance was assessed using the Eriksen flanker task (multiple-choice response time). Significant reductions (P < 0.05) were observed in distance covered and high-speed running during the second half when compared to the first. No significant differences (P > 0.05) in psychomotor performance at different time points were observed. Response time was significantly improved when running above 65% of maximal sprinting speed (P < 0.01). This data questions the application of the inverted-U hypothesis for intermittent exercise and suggests that the short high-intensity efforts may not result in the same physiological events that limit psychomotor performance during sustained high-intensity exercise. More so, the high-intensity efforts during the match protocol appeared to promote psychomotor performance during the intermittent exercise

Incorporating perceptual decision-making training into high-intensity interval training for Australian football umpires

Existing methods for developing decision–making skill for Australian football umpires separate the physical and perceptual aspects of their performance. This study aimed to determine the efficacy of incorporating video-based decision-making training during high-intensity interval training sessions, specific for Australian football umpires. 20 amateur Australian football umpires volunteered to participate in a randomised control trial. Participants completed an 8-week training intervention in a conditioning only (CON; n=7), combined video-based training and conditioning (COM; n=7), or separated conditioning and video-based training (SEP; n=6) group. Preliminary and post-testing involved a Yo-Yo Intermittent Recovery Test (Yo-YoIR1), and 10x300m run test with an Australian football specific video-based decision-making task. Overall, changes in decision-making accuracy following the intervention were unclear between groups. SEP was possibly beneficial compared to COM in Yo-YoIR1 performance, whereas CON was likely beneficial compared to COM in 10x300m sprint performance. There was no additional benefit to completing video-based training, whether combined with, or separate to physical training, suggesting that this was not an optimal training method. For video-based training to be an effective decision-making tool, detailed feedback should be incorporated into training. It is recommended that longer conditioning and video-based training interventions be implemented to determine training effectiveness. © 2018, © 2018 Informa UK Limited, trading as Taylor & Francis Group