ORCID Profile
0000-0002-8177-7262
Current Organisation
Deakin University
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Publisher: Public Library of Science (PLoS)
Date: 22-10-2020
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 03-2012
Publisher: Aerospace Medical Association
Date: 06-2010
Abstract: We aimed to make recommendations concerning the use of total IgA in saliva (s-IgA) as an aid for monitoring athletic and military training. Unstimulated whole saliva was collected from 16 subjects (11 women and 5 men ages 18-57) during nonconsecutive days of fasting and non-fasting. Seven s les were collected from each subject at 0700, 0900, 1200, 1400, 1600, 1800, and 2030 on each day and a further three s les were collected 30 min after three meals on the non-fasting day (at 0730, 1230, and 1830). Strenuous activity was avoided and subjects did not drink caffeine or alcohol-containing beverages. Albumin and s-IgA were measured by commercial nephelometric immunoassays with intra-analytical coefficient of variance (CVA) of 1.8% and 2.9%, respectively. In idual and group variations were determined. Diurnal variation was determined by use of repeated-measures analysis of variance. CV-in idual (CV(I)) was 48% for s-IgA concentration and 43% for s-IgA secretion and s-IgA:albumin. CV-group (CVG) for these same measures was 68%, 75%, and 68%, respectively. When measurements were adjusted for saliva flow rates there was no evidence that s-IgA is subject to diurnal variation. There was strong evidence for a postprandial decrease in s-IgA for all measures. The high degree of in iduality in s-IgA precludes the use of population reference ranges for identifying in idual abnormal results. For the purpose of monitoring in iduals we recommend using the in idual's calculated biological variance (determined from previous serial measurements over a period of days to weeks). In idual abnormal results can then be identified.
Publisher: Human Kinetics
Date: 10-2017
Abstract: Most previous investigations of player load in netball have used subjective methodologies, with few using objective methodologies. While all studies report differences in player activities or total load between playing positions, it is unclear how the differences in player activity explain differences in positional load. To objectively quantify the load associated with typical activities for all positions in elite netball. The player load of all playing positions in an elite netball team was measured during matches using wearable accelerometers. Video recordings of the matches were also analyzed to record the start time and duration of 13 commonly reported netball activities. The load associated with each activity was determined by time-aligning both data sets (load and activity). Off-ball guarding produced the highest player load per instance, while jogging produced the greatest player load per match. Nonlocomotor activities contributed least to total match load for attacking positions (goal shooter [GS], goal attack [GA], and wing attack [WA]) and most for defending positions (goalkeeper [GK], goal defense [GD], and wing defense [WD]). Specifically, centers (Cs) produced the greatest jogging load, WA and WD accumulated the greatest running load, and GS and WA accumulated the greatest shuffling load. WD and Cs accumulated the greatest guarding load, while WD and GK accumulated the greatest off-ball guarding load. All positions exhibited different contributions from locomotor and nonlocomotor activities toward total match load. In addition, the same activity can have different contributions toward total match load, depending on the position. This has implications for future design and implementation of position-specific training programs.
Publisher: Informa UK Limited
Date: 16-07-2016
DOI: 10.1080/02640414.2015.1065341
Abstract: Performance in triathlon is dependent upon factors that include somatotype, physiological capacity, technical proficiency and race strategy. Given the multidisciplinary nature of triathlon and the interaction between each of the three race components, the identification of target split times that can be used to inform the design of training plans and race pacing strategies is a complex task. The present study uses machine learning techniques to analyse a large database of performances in Olympic distance triathlons (2008-2012). The analysis reveals patterns of performance in five components of triathlon (three race "legs" and two transitions) and the complex relationships between performance in each component and overall performance in a race. The results provide three perspectives on the relationship between performance in each component of triathlon and the final placing in a race. These perspectives allow the identification of target split times that are required to achieve a certain final place in a race and the opportunity to make evidence-based decisions about race tactics in order to optimise performance.
Publisher: Elsevier BV
Date: 09-2014
DOI: 10.1016/J.JSAMS.2013.08.002
Abstract: No study has investigated the influence of field position and phase of play on the physical demands of match-play in professional rugby league forwards. We investigated the physical demands placed on forwards in elite rugby league matches, with special reference to how these demands differed between attack and defence, and in different field positions. Cohort study. Twenty-two rugby league players (26 ± 3 years) from the same professional club participated in this study. Global positioning system (GPS) analysis was completed during 23 matches. Video footage was synchronised with the GPS files and coded for the time spent in attack and defence, and in one of three different field positions (0-30 m, 31-70 m, 71-100 m). The physical demands of defence were consistently greater than attack. Moderate to large differences (ES=0.62-1.41) were found between defence and attack for distance covered (109 ± 16 m/min vs. 82 ± 12 m/min), low speed distance (104 ± 15 m/min vs. 78 ± 11 m/min), frequency of collisions (1.9 ± 0.7/min vs. 0.8 ± 0.3/min), and repeated high-intensity effort bouts (1 every 4.9 ± 5.1 min vs. 1 every 9.4 ± 6.1 min). The running demands and frequency of repeated high-intensity effort bouts were greater when defending in the opposition's 30 m zone (i.e. 71-100 m), with repeated high-intensity effort bouts also occurring more frequently when defending the team's own try-line and when attacking the opposition's try-line. Specific training drills designed to replicate the attacking and defensive demands of different field positional zones are likely to be effective in preparing players for the most demanding activities that occur in professional rugby league match-play.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 03-2016
Publisher: Walter de Gruyter GmbH
Date: 07-2019
Abstract: Mathematical models that explain match outcome, based on the value of technical performance indicators (PIs), can be used to identify the most important aspects of technical performance in team field-sports. The purpose of this study was to evaluate several methodological opportunities, to enhance the accuracy of this type of modelling. Specifically, we evaluated the potential benefits of 1) modelling match outcome using an increased number of seasons and PIs compared with previous reports, 2) how to identify eras where technical performance characteristics were stable and 3) the application of a novel feature selection method. Ninety-one PIs across sixteen Australian Football (AF) League seasons were analysed. Change-point and Segmented Regression analyses were used to identify eras and they produced similar but non-identical outcomes. A feature selection ensemble method identified the most valuable 45 PIs for modelling. The use of a larger number of seasons for model development lead to improvement in the classification accuracy of the models, compared with previous studies (88.8 vs 78.9%). This study demonstrates the potential benefits of large databases when creating models of match outcome and the pitfalls of determining whether there are eras in a longitudinal database.
Publisher: SAGE Publications
Date: 29-07-2009
Abstract: Total immunoglobulin A in saliva (s-IgA) is normally assayed using an enzyme-linked immunosorbent assay. We have investigated methodological issues relating to the use of particle-enhanced nephelometric immunoassay (PENIA) to measure s-IgA in whole unstimulated saliva and determine its reference range. Whole unstimulated resting saliva was collected to determine s le stability (temperature, time, effect of a protease inhibitor), limit of quantitation (LOQ), assay precision and analytical variation. The reference range for 134 healthy adults was determined. Linearity was excellent (4–10.3 mg L −1 , P 0.001 R 2 = 0.997) and without significant bias (mean of −0.7%). The lowest intra- and inter-analytical coefficients of variation were 1.8% and 7.5% and LOQ was 1.4 mg L −1 . The concentration of s-IgA is stable at room temperature for up to 6 h, at 4°C for 48 h, at −4°C for two weeks and at −80°C for up to 1.3 yr. There is no evidence that a protease inhibitor increases the stability or that repeated freeze–thawing cycles degrade s le quality. The reference ranges for s-IgA concentration, s-IgA secretion, s-IgA:albumin and s-IgA:osmolality were 15.9–414.5 mg L −1 , 7.2–234.9 μg min −1 , 0.4–19 and 0.6–8.9, respectively. Automated PENIA assay of s-IgA is precise and accurate. High stability of collected saliva s les and the ease and speed of the assay make this an ideal method for use in athletic and military training situations. The convenience of measuring albumin and IgA on the same analytical platform adds to the practicability of the test.
Publisher: Human Kinetics
Date: 12-2016
Abstract: Sodium citrate induces alkalosis and can provide a performance benefit in high-intensity exercise. Previous investigations have been inconsistent in the ingestion protocols used, in particular the dose and timing of ingestion before the onset of exercise. The primary aim of the current study was to quantify blood pH, blood bicarbonate concentration and gastrointestinal symptoms after ingestion of three doses of sodium citrate (500 mg⋅kg -1 , 700 mg⋅kg -1 and 900 mg⋅kg -1 ). Thirteen participants completed four experimental sessions, each consisting of a different dose of sodium citrate or a taste-matched placebo solution. Blood pH and blood bicarbonate concentration were measured at 30-min intervals via analysis of capillary blood s les. Gastrointestinal symptoms were also monitored at 30-min intervals. Statistical significance was accepted at a level of p .05. Both measures of alkalosis were significantly greater after ingestion of sodium citrate compared with placebo ( p .001). No significant differences in alkalosis were found between the three sodium citrate doses ( p .05). Peak alkalosis following sodium citrate ingestion ranged from 180 to 212 min after ingestion. Gastrointestinal symptoms were significantly higher after sodium citrate ingestion compared with placebo ( p .001), while the 900 mg.kg -1 dose elicited significantly greater gastrointestinal distress than 500 mg⋅kg -1 ( p = .004). It is recommended that a dose of 500 mg⋅kg -1 of sodium citrate should be ingested at least 3 hr before exercise, to achieve peak alkalosis and to minimize gastrointestinal symptoms before and during exercise.
Publisher: Human Kinetics
Date: 11-2016
Abstract: The activity profile of competition and training in elite netball has not been comprehensively reported in the literature. To measure and analyze player load in elite netballers during matches and training sessions. The primary research question was, How does player load vary between playing positions in a match and between matches and training sessions? Various measures of player load were recorded in 12 elite professional netballers with a mean ± SD age of 26 ± 4.9 y and height of 183.2 ± 8.7 cm. Player load was assessed using a published method that uses accelerometry. Load was represented as total load in arbitrary units (au), playing intensity (au/min), and relative time spent in each of 4 playing intensity zones (low, low to moderate, moderate, and high). Data from 15 games and up to 17 training sessions were analyzed for each player. Player load in matches for the goal-based positions (goal shooter, goal keeper, and goal defense) tended to be lower than the attacking and wing-based positions (goal attack, wing attack, wing defense, and center). The difference was largely due to the amount of time spent in low-intensity activity. Playing intensity of matches was greater than in training sessions however, the total time spent in moderate- to high-intensity activities was not practically different. Accelerometry is a valuable method of measuring player load in netball, and the present results provide new information about the activity profile of different playing positions.
Publisher: Elsevier BV
Date: 06-2013
Publisher: Elsevier BV
Date: 02-2019
DOI: 10.1016/J.JSAMS.2018.07.017
Abstract: The purpose of this study was to provide a profile of the demographics and employment characteristics of the Australian high performance and sport science workforce. This study used a cross-sectional, quantitative survey methodology to collect data about the Australian high performance and sport science workforce. 175 Australian high performance and sport science employees completed an online survey which captured demographic information and work-related characteristics such as role, industry sector, income, permanence of employment and hours worked. Descriptive statistics were used to summarise information and some comparisons were made between position titles, industry sectors and sexes. The Australian high performance and sport science workforce is predominantly male (76.0%), ≤35 years of age (50.3%), located on the eastern seaboard of Australia (69%) and have been in their current position for 2-5 years (37.4%). They are mostly employed on a fixed term contract of 2.4 years, by an institute of sport. Income varied, with those working in professional sporting clubs and/or employed as high performance managers earning the highest wage. On average, participants worked well over their contracted hours, with a considerable proportion of these hours outside the standard 9-5 working week. Employees in the high performance and sport science workforce in Australia face significant professional issues that relate to long and unusual work hours, job insecurity and income disparity. Policy makers and the managers of this workforce should consider the impact of these issues on work-life balance, staff retention rates and the risk of burnout.
Publisher: Informa UK Limited
Date: 11-04-2019
Publisher: Informa UK Limited
Date: 05-2013
DOI: 10.1080/02640414.2012.757344
Abstract: This article describes the utilisation of an unsupervised machine learning technique and statistical approaches (e.g., the Kolmogorov-Smirnov test) that assist cycling experts in the crucial decision-making processes for athlete selection, training, and strategic planning in the track cycling Omnium. The Omnium is a multi-event competition that will be included in the summer Olympic Games for the first time in 2012. Presently, selectors and cycling coaches make decisions based on experience and intuition. They rarely have access to objective data. We analysed both the old five-event (first raced internationally in 2007) and new six-event (first raced internationally in 2011) Omniums and found that the addition of the elimination race component to the Omnium has, contrary to expectations, not favoured track endurance riders. We analysed the Omnium data and also determined the inter-relationships between different in idual events as well as between those events and the final standings of riders. In further analysis, we found that there is no maximum ranking (poorest performance) in each in idual event that riders can afford whilst still winning a medal. We also found the required times for riders to finish the timed components that are necessary for medal winning. The results of this study consider the scoring system of the Omnium and inform decision-making toward successful participation in future major Omnium competitions.
Publisher: Elsevier BV
Date: 11-2018
Publisher: Public Library of Science (PLoS)
Date: 21-06-2022
DOI: 10.1371/JOURNAL.PONE.0269330
Abstract: Understanding reliability of performance analysis tools is important to ensure match to match comparisons can be undertaken with the knowledge of consistency between coding situations. There are few published studies examining the reliability of commonly used performance analysis tools. The aim of this project was to assess the inter- and intra-rater reliability of the NetballStats application and to make comparisons between live and video-based coding situations. Two ‘coders’ coded eight netball matches using the NetballStats application, coding each match live, then twice from video. Level of agreement was assessed for frequency counts across the variables coded. Results showed that intra-rater agreement was higher than inter-rater agreement and that reliability from video coding is better than from live coding. High frequency events automatically coded by the application and events that are well defined had greater levels of agreement than lower frequency events and subjectively judged events. Live coding situations underrepresent occurrence of events, particularly for high frequency events such as ‘possession’. To ensure reliability between coders, clubs should provide an extensive training program to coders with clear instructions on coding subjective events. Coaches should be aware that live coding underestimates some event types and factor this into their decision making processes.
Publisher: Informa UK Limited
Date: 29-10-2022
Publisher: Springer Berlin Heidelberg
Date: 2010
Publisher: Informa UK Limited
Date: 08-06-2021
Publisher: Elsevier BV
Date: 11-2017
Publisher: Springer Science and Business Media LLC
Date: 02-2010
DOI: 10.2165/11319670-000000000-00000
Abstract: There is currently no universally recommended and accepted method of data processing within the science of indirect calorimetry for either mixing chamber or breath-by-breath systems of expired gas analysis. Exercise physiologists were first surveyed to determine methods used to process oxygen consumption ((.)VO2) data, and current attitudes to data processing within the science of indirect calorimetry. Breath-by-breath datasets obtained from indirect calorimetry during incremental exercise were then used to demonstrate the consequences of commonly used time, breath and digital filter post-acquisition data processing strategies. Assessment of the variability in breath-by-breath data was determined using multiple regression based on the independent variables ventilation (VE), and the expired gas fractions for oxygen and carbon dioxide, FEO2 and FECO2, respectively. Based on the results of explanation of variance of the breath-by-breath (.)VO2 data, methods of processing to remove variability were proposed for time-averaged, breath-averaged and digital filter applications. Among exercise physiologists, the strategy used to remove the variability in (.)VO2 measurements varied widely, and consisted of time averages (30 sec [38%], 60 sec [18%], 20 sec [11%], 15 sec [8%]), a moving average of five to 11 breaths (10%), and the middle five of seven breaths (7%). Most respondents indicated that they used multiple criteria to establish maximum ((.)VO2 ((.)VO2max) including: the attainment of age-predicted maximum heart rate (HR(max)) [53%], respiratory exchange ratio (RER) >1.10 (49%) or RER >1.15 (27%) and a rating of perceived exertion (RPE) of >17, 18 or 19 (20%). The reasons stated for these strategies included their own beliefs (32%), what they were taught (26%), what they read in research articles (22%), tradition (13%) and the influence of their colleagues (7%). The combination of VE, FEO2 and FECO2 removed 96-98% of (.)VO2 breath-by-breath variability in incremental and steady-state exercise (.)VO2 data sets, respectively. Correction of residual error in (.)VO2 datasets to 10% of the raw variability results from application of a 30-second time average, 15-breath running average, or a 0.04 Hz low cut-off digital filter. Thus, we recommend that once these data processing strategies are used, the peak or maximal value becomes the highest processed datapoint. Exercise physiologists need to agree on, and continually refine through empirical research, a consistent process for analysing data from indirect calorimetry.
Publisher: Informa UK Limited
Date: 27-06-2022
DOI: 10.1080/14763141.2022.2092029
Abstract: The aim of the study was to compare the Force-Velocity profiles of track sprint cyclists obtained in seated and non-seated positions. Athletes were tested on a stationary cycle ergometer for the seated position and on a racing bike at the velodrome for the non-seated position. We modelled torque and power vs. cadence relationships and extracted maximal force (F
Publisher: Public Library of Science (PLoS)
Date: 13-04-2022
DOI: 10.1371/JOURNAL.PONE.0266830
Abstract: Studies of training and competition load in sport are usually based on data that represents a s le of a league and or annual training program. These studies sometimes explore important factors that are affected by load, such as training adaptations and injury risk. The generalisability of the conclusions of these studies, can depend on how much load varies between seasons, training phases and teams. The interpretation of previous load studies and the design of future load studies should be influenced by an understanding of how load can vary across seasons, training phases and between teams. The current study compared training loads (session rating of perceived exertion x session duration) between all (8) teams in an elite Netball competition for multiple (2) season phases and (2) seasons. A total of 29,545 records of athlete session training loads were included in the analysis. Linear mixed models identified differences between seasons and training phases (p .05). There were also differences between teams and a complex set of interactions between these three factors (season, phase, and team) (p .05). While the absolute value of the training loads reported here are only relevant to elite netball, these results illustrate that when data is s led from a broader context, the range and variation in load may increase. This highlights the importance of cautiously interpreting and generalisation of findings from load studies that use limited data sets.
Publisher: Elsevier BV
Date: 12-1999
DOI: 10.1016/S1440-2440(99)80006-1
Abstract: The purpose of this study was to examine whether a single biopsy s le of vastus lateralis could provide an accurate estimate of capillary density (CD) which is indicative of the entire muscle, or whether capillary density is distributed unevenly and varies with muscle depth. Whole muscle cross sections of vastus lateralis were excised post mortem (n=11) for analysis of capillary density at three muscle depths, (superficial, mid and deep regions). Muscle thickness varied widely (17-79 mm) across subjects. The distribution of CD throughout the depth of the muscle was homogeneous in 8 subjects, but in 3 subjects it was heterogeneous (p<0.05). In 3 of these subjects there was a significant (p<0.05) effect of s le depth on CD. These data indicate that tissue from a single biopsy will not adequately represent the CD of the entire vastus lateralis in some in iduals. Single biopsies from unspecified muscle depth, have routinely been used to estimate CD and fibre type in vastus lateralis. The present study indicates that a more reliable method of analysis would be to use the tissue from two needle biopsies taken at the superficial and deep portions of the muscle from a group of at least 10 subjects. S ling theory analysis supported this conclusion.
Publisher: Wiley
Date: 2002
DOI: 10.1113/EPH8702176
Abstract: An increase in the concentration of serotonin in the brain has been shown to cause fatigue during exercise in humans and experimental animals. This type of fatigue is referred to as central fatigue and is likely to be mediated by the concentration of serotonin as well as serotonin receptor sensitivity. Serotonin (5-HT) receptor antagonism in humans and experimental animals has been shown to improve endurance performance. A previous report has shown decreased receptor sensitivity in athletes compared to sedentary controls. It is unclear whether this is due to a training adaptation or if in iduals are predisposed to enhanced athletic performance due to their inherent decreased receptor sensitivity. The present study investigated changes in 5-HT receptor sensitivity in response to aerobic exercise. Subjects completed 3 x 30 min of stationary cycling at 70 % of their peak aerobic power (.V(O(2)peak)) for 9 weeks. Serotonin receptor sensitivity was assessed indirectly by measuring the neuroendocrine response following administration of a serotonin agonist (buspirone hydrochloride). The neuroendocrine response following administration of a placebo was also investigated in a blind crossover design. A group of sedentary control subjects was also recruited to control for seasonal variations in central receptor sensitivity. The training caused a significant increase in .V(O(2)peak)) (3.1 +/- 0.16 to 3.6 +/- 0.15 l min(-1), P < 0.05) and endurance capacity (93 +/- 8 to 168 +/- 11 min, P 0.05) in the neuroendocrine response in the presence of a serotonin agonist. However, one-quarter of the subjects in the training group demonstrated decreases in receptor sensitivity. These results suggest that despite increases in .V(O(2)peak)) and endurance performance, there was no measurable change in 5-HT receptor sensitivity in the presence of a serotonin agonist. In addition, it is possible that changes in receptor sensitivity may take longer to occur, that the training stimulus used in the present investigation was inadequate and/or that changes occurred in receptor subtypes that were not probed by the agonist used in the present investigation.
Publisher: Elsevier BV
Date: 2019
DOI: 10.1016/J.JSAMS.2018.06.005
Abstract: The purpose of this study was to investigate the effects of match characteristics and elite level umpiring experience on the decision-making performance of umpires in the Australian Football League (AFL). Cross Sectional Study. All decisions from the 2014 AFL home and away season made by 32 male AFL field umpires (age 33.1±5.0years, AFL umpire experience 122±105 matches) were classified by a panel of four expert umpire coaches into correct, missed and unwarranted categories. The 8001 decisions were then further categorised based on the match time, score differential, field location, home ground advantage, match attendance and elite level umpiring experience. Chi-square with standardised residuals and two-way analysis of variance were used to analyse the data. Higher elite level umpiring experience and a larger score differential at the time of the decision resulted in improved decision-making accuracy. Home ground advantage, attendance and match time did not influence the decision-making performance of umpires. Impact averse decisions occurred in the back line of play, with umpires tending to be conservative with decisions that may impact the score. Decisions that have an increased influence on an umpire's decision-making performance include score differential and elite umpiring experience. Implications on umpiring performance regarding the venue, attendance and the duration of a match were not apparent.
Publisher: Informa UK Limited
Date: 27-05-2021
Publisher: Elsevier BV
Date: 11-2017
Publisher: Informa UK Limited
Date: 04-03-2022
Publisher: BMJ
Date: 26-06-2020
DOI: 10.1136/BJSPORTS-2018-100029
Abstract: To determine whether specific injury measures were associated with team performance in the Australian Football League (AFL). 15 289 injuries caused players from 18 teams to miss 51 331 matches between 1997 and 2016. Data were aggregated to the team level. We analysed the associations among injury measures and team performance (reaching finals layoffs and specific ladder/table position). Injury measures per team included: injury incidence, injury severity, injury burden, player match availability and percentage of the full player roster injured. We also weighted injury measures by five measures of player value. AFL teams' injury burden and player match availability were associated with final table position (r The impact of injury (burden weighted by best and fairest) explained up to 12% of the variation in final table position-this is particularly relevant to making/not making playoffs as well as home ground/travel advantages for those teams that make the one-game format of AFL playoffs (not home-away or best of seven format).
Publisher: Human Kinetics
Date: 12-2022
Abstract: Purpose : To determine whether the most important physical qualities in elite Australian male and female cricket pace bowlers change with age and phase of the cricket season. Methods : An existing longitudinal database (7 cricket seasons) of selected and routinely collected physical testing data from 103 male and 58 female elite Australian pace bowlers age 18–30 years was retrospectively analyzed. Male and female physical testing data from the isometric midthigh pull, 1-repetition-maximum bench pull, run-of-3, and countermovement jump (male only) were analyzed separately by performing linear mixed models on each of the physical qualities. Type III analysis-of-variance tests were conducted to determine if a significant effect existed within the fixed effects of age, season phase, and the age × season phase interaction. Appropriate pairwise comparisons were conducted. Results : Absolute and relative measures of force in the isometric midthigh pull and strength in the 1-repetition-maximum bench pull tests were significantly greater in older male and female pace bowlers. Older male pace bowlers demonstrated significantly faster absolute and relative best run-of-3 times. Conclusions : Most physical qualities across both male and female pace bowlers demonstrated an improvement with age. This is likely due to a training effect and would be anticipated to lead to a gradual enhancement of ball release speed, in accordance with previous research. Future research should look to investigate the relationship between the development of physical qualities and ball release speed among elite male and female pace bowlers.
Publisher: SAGE Publications
Date: 04-2019
Abstract: Injury surveillance has been used to quantify the scope of the injury burden in Australian football. However, deeper statistical analyses are required to identify major factors that contribute to the injury risk and to understand how these injury patterns change over time. To compare Australian Football League (AFL) injury incidence, severity, prevalence, and recurrence by setting, site, and time span from 1997 to 2016. Descriptive epidemiology study. A total of 15,911 injuries and medical illnesses recorded by team medical staff at each club were obtained from the AFL’s injury surveillance system and analyzed using linear mixed models with 3 fixed effects (setting, time span, site) and 1 random effect (club). All types of injuries and medical illnesses were included for analysis, provided that they caused the player to miss at least 1 match during the regular season or finals. Five-season time spans (1997-2001, 2002-2006, 2007-2011, and 2012-2016) were used for comparisons. Incidence rates were expressed at the player level. Recurrences were recoded to quantify recurrent injuries across multiple seasons. Compared with training injuries, match injuries had a 2.8 times higher incidence per season per club per player (matches: 0.070 ± 0.093 training: 0.025 ± 0.043 P .001). Match injuries resulted in 1.9 times more missed matches per club per season (matches: 17.2 ± 17.0 training: 9.1 ± 10.5 P .001). and were more likely to be recurrences (matches: 11.6% ± 20.0% training: 8.6% ± 21.8% P .001). From the 1997-2001 to 2007-2011 time spans, overall injury severity increased from a mean of 3.2 to 3.7 missed matches ( P ≤ .01). For the most recent 2012-2016 time span, injuries resulted in 3.6 missed matches, on average. Hip/groin/thigh injuries had the highest incidence (0.125 ± 0.120) and prevalence (19.2 ± 16.4) rates, and recurrences (29.3% ± 27.9%) were 15% more likely at this site than any other injury site. The risks of match injuries are significantly higher than those of training injuries in the AFL. Compared with the 1997-2001 time span, injuries became more severe during the 2007-2011 time span.
Publisher: Human Kinetics
Date: 04-2015
Abstract: To compare a novel sprint test on a cycle ergometer with a countermovement-jump (CMJ) test for monitoring neuromuscular fatigue after Australian rules football match play. Twelve elite under-18 Australian rules football players (mean ± SD age 17.5 ± 0.6 y, stature 184.7 ± 8.8 cm, body mass 75.3 ± 7.8 kg) from an Australian Football League club’s Academy program performed a short sprint test on a cycle ergometer along with a single CMJ test 1 h prematch and 1, 24, and 48 h postmatch. The cycle-ergometer sprint test involved a standardized warm-up, a maximal 6-s sprint, a 1-min active recovery, and a 2nd maximal 6-s sprint, with the highest power output of the 2 sprints recorded as peak power (PP). There were small to moderate differences between postmatch changes in cycle-ergometer PP and CMJ PP at 1 (ES = 0.49), 24 (ES = –0.85), and 48 h postmatch (ES = 0.44). There was a substantial reduction in cycle-ergometer PP at 24 h postmatch (ES = –0.40) compared with 1 h prematch. The cycle-ergometer sprint test described in this study offers a novel method of neuromuscular-fatigue monitoring in team-sport athletes and specifically quantifies the concentric component of the fatigue-induced decrement of force production in muscle, which may be overlooked by a CMJ test.
Publisher: Journal of Science and Cycling
Date: 09-10-2019
Abstract: The accuracy and reliability of instrumented bicycle crank systems (i.e. power meters) is an important consideration for sport scientists who evaluate cycling performance and pedalling biomechanics. Many crank systems report power and or force/s on the left and right crank arms separately, or indexes of pedalling effectiveness, although crank systems that have genuinely independent force transducers on the left and right crank arms are rare. There is a need to be able to evaluate the accuracy and reliability of the measurements of power meters without the requirement for expensive and or complex instrumentation. The present study describes a relatively simple and novel method of assessing the accuracy and reliability of measures of crank angle, radial force and tangential force. The method is demonstrated in its application to an instrumented crank system (Axis Cranks ™). Reported crank forces were compared with actual applied forces to determine accuracy and some procedures used to assess the measurement of force were duplicated to determine reliability. The crank system measured crank angle with an average RMS error of 1.84 degrees across pedalling rates of 30-150 r/min. The absolute error of radial and tangential force measurements were 6% and 3.2% respectively (RMSE) and the relative error (accuracy of change in force) of radial and tangential force were 1.48% and 0.25% respectively (RMSE). Repeated measurements of force were found to be highly reliable (intra-class coefficient 0.998). The method presented in this report could be used to evaluate the accuracy and reliability of other power meters and instrumented crank systems.
Publisher: Springer Science and Business Media LLC
Date: 2003
Publisher: Elsevier BV
Date: 03-2018
DOI: 10.1016/J.JSAMS.2017.07.022
Abstract: The purpose of this study was to assess the validity of the ActiGraph GT3X+ (GT3X+) and the BodyMedia SenseWear Armband (SWA) to estimate energy expenditure (EE) during physical activity and field sport movements. Criterion validity. Twenty-six active adults completed a single 90min session involving alternating intervals of exercise (5min) and recovery (10min). Exercise involved walking (4km/h), jogging (8km/h), running (12km/h) or a sport-simulated circuit (three intervals). Participants wore two triaxial accelerometers (GT3X+ and SWA) and a portable gas analyser (MetaMax 3B), used as the criterion measure. Total EE was significantly underestimated (p<0.01) by the GT3X+ (mean bias±SD: -374.5±132.84kJ % difference=-29.3%) and SWA (-244.3±148.0kJ -18.2%). Overestimations were made by both accelerometers during the walk (GT3X+: 27.4±30.8kJ SWA: 32.1±15.4kJ) and jog (38.0±30.0kJ 34.5±31.6kJ). Underestimations were evident during the run (-41.2±25.1kJ -43.8±33.5kJ) and circuit (C1: GTX+: -127.2±41.6kJ SWA: -86.1±40.2kJ). Error of estimation increased in magnitude as the intensity of exercise increased (GT3X+: 40.8-143.0kJ SWA: 35.5-102.0kJ). The ActiGraph GT3X+ and BodyMedia SWA do not provide valid EE estimates across a range of exercise modalities and intensities when compared to a criterion measure. Poor accuracy and large precision errors, particularly during high intensity and intermittent movement patterns, suggest these devices have limitations and should be used cautiously in the field.
Publisher: Wiley
Date: 07-11-2000
Publisher: Human Kinetics
Date: 11-2016
Abstract: The purpose of this study was to assess the validity of a global positioning system (GPS) tracking system to estimate energy expenditure (EE) during exercise and field-sport locomotor movements. Twenty-seven participants each completed a 90-min exercise session on an outdoor synthetic futsal pitch. During the exercise session, they wore a 5-Hz GPS unit interpolated to 15 Hz and a portable gas analyzer that acted as the criterion measure of EE. The exercise session was composed of alternating 5-minute exercise bouts of randomized walking, jogging, running, or a field-sport circuit (×3) followed by 10 min of recovery. One-way analysis of variance showed significant ( P .01) and very large underestimations between GPS metabolic power– derived EE and oxygen-consumption (VO 2 ) -derived EE for all field-sport circuits (% difference ≈ –44%). No differences in EE were observed for the jog (7.8%) and run (4.8%), whereas very large overestimations were found for the walk (43.0%). The GPS metabolic power EE over the entire 90-min session was significantly lower ( P .01) than the VO 2 EE, resulting in a moderate underestimation overall (–19%). The results of this study suggest that a GPS tracking system using the metabolic power model of EE does not accurately estimate EE in field-sport movements or over an exercise session consisting of mixed locomotor activities interspersed with recovery periods however, is it able to provide a reasonably accurate estimation of EE during continuous jogging and running.
Publisher: Informa UK Limited
Date: 07-02-2020
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 2020
Publisher: CSIRO Publishing
Date: 2004
DOI: 10.1071/HE04134
Publisher: Elsevier BV
Date: 04-2019
DOI: 10.1016/J.JSAMS.2018.09.235
Abstract: To identify novel insights about performance in Australian Football (AF), by modelling the relationships between player actions and match outcomes. This study extends and improves on previous studies by utilising a wider range of performance indicators (PIs) and a longer time frame for the development of predictive models. Observational. Ninety-one team PIs from the 2001 to 2016 Australian Football League seasons were used as independent variables. The categorical Win-Loss and continuous Score Margin match outcome measures were used as dependent variables. Decision tree and Generalised Linear Models were created to describe the relationships between the values of the PIs and match outcome. Decision tree models predicted Win-Loss and Score Margin with up to 88.9% and 70.3% accuracy, respectively. The Generalised Linear Models predicted Score Margin to within 6.8 points (RMSE) and Win-Loss with up to 95.1% accuracy. The PIs that are most predictive of match outcome include Turnovers Forced score, Inside 50s per shot, Metres Gained and Time in Possession, all in their relative (to opposition) form. The decision trees illustrate how combinations of the values of these PIs are associated with match outcome, and they indicate target values for these PIs. This work used a wider range of PIs and more historical data than previous reports and consequently demonstrated higher prediction accuracies and additional insights about important indicators of performance. The methods used in this work can be implemented by other sport analysts to generate further insights that support the strategic decision-making processes of coaches.
No related grants have been discovered for Dan Dwyer.