Measurement Characteristics of Athlete Monitoring Tools in Professional Australian Football.

PURPOSE: To examine the measurement reliability and sensitivity of common athlete monitoring tools in professional Australian Football players. METHODS: Test-retest reliability (noise) and weekly variation (signal) data were collected from 42 professional Australian footballers from 1 club during a competition season. Perceptual wellness was measured via questionnaires completed before main training sessions (48, 72, and 96 h postmatch), with players providing a rating (1-5 Likert scale) regarding their muscle soreness, sleep quality, fatigue level, stress, and motivation. Eccentric hamstring force and countermovement jumps were assessed via proprietary systems once per week. Heart rate recovery was assessed via a standard submaximal run test on a grass-covered field with players wearing a heart rate monitor. The heart rate recovery was calculated by subtracting average heart rate during final 10 seconds of rest from average heart rate during final 30 seconds of exercise. Typical test error was reported as coefficient of variation percentage (CV%) and intraclass coefficients. Sensitivity was calculated by dividing weekly CV% by test CV% to produce a signal to noise ratio. RESULTS: All measures displayed acceptable sensitivity. Signal to noise ratio ranged from 1.3 to 11.1. Intraclass coefficients ranged from .30 to .97 for all measures. CONCLUSIONS: The heart rate recovery test, countermovement jump test, eccentric hamstring force test, and perceptual wellness all possess acceptable measurement sensitivity. Signal to noise ratio analysis is a novel method of assessing measurement characteristics of monitoring tools. These data can be used by coaches and scientists to identify meaningful changes in common measures of fitness and fatigue in professional Australian football.

Physical Preparation Factors That Influence Technical and Physical Match Performance in Professional Australian Football.

OBJECTIVES: To examine the collective influence of a range of physical preparation elements on selected performance measures during Australian football match play. DESIGN: Prospective and longitudinal. METHODS: Data were collected from 34 professional Australian football players from the same club during the 2016 Australian Football League competition season. Match activity profiles and acute (7-d) and chronic (3-wk) training loads were collected using global positioning system devices. Training response was measured by well-being questionnaires completed prior to the main training session each week. Maximal aerobic running speed (MAS) was estimated by a 2-km time trial conducted during preseason. Coach ratings were collected from the senior coach and 4 assistants after each match on a 5-point Likert scale. Player ratings were obtained from a commercial statistics provider. Fifteen matches were analyzed. Linear mixed models were constructed to examine the collective influence of training-related factors on 4 performance measures. RESULTS: Muscle soreness had a small positive effect (ES: 0.12) on Champion Data rating points. Three-week average high-speed running distance had a small negative effect (ES: 0.14) on coach ratings. MAS had large to moderate positive effects (ES: 0.55 to 0.47) on relative total and high-speed running distances. Acute total and chronic average total running distance had small positive (ES: 0.13) and negative (ES: 0.14) effects on relative total and high-speed running distance performed during matches, respectively. CONCLUSIONS: MAS should be developed to enhance players' running performance during competition. Monitoring of physical preparation data may assist in reducing injury and illness and increasing player availability but not enhance football performance.

Interchange rotation factors and player characteristics influence physical and technical performance in professional Australian Rules football.

OBJECTIVES: To examine the effects of match-related and individual player characteristics on activity profile and technical performance during rotations in professional Australian football. DESIGN: Longitudinal observational study. METHODS: Global positioning system data and player rating scores were collected from 33 professional Australian football players during 15 Australian football League matches. Player rating scores were time aligned with their relative total and high-speed running (HSR) distance (>20kmh-1) for each on ground rotation. Individual players' maximal aerobic running speed (MAS) was determined from a two-kilometre trial. A multilevel linear mixed model was used to examine the influence of rotations on physical activity profiles and skill execution during match play. RESULTS: Rotation duration and accumulated distance resulted in a trivial-to-moderate reduction in relative total and HSR distances as well as relative rating points. The number of disposals in a rotation had a small positive effect on relative total and HSR distances and a large positive effect on relative rating points. MAS was associated with a moderate-to-large increase in relative total distance, but had a large negative effect on relative rating points. Previous rotation time, stoppages and the number of rotations in the quarter had a trivial-to-small negative effect on relative total and HSR distances. A greater speed (mmin-1) was associated with a trivial increase in rating points during a rotation, while there was a trivial decrease in relative total distance as rating points increased. CONCLUSION: The complex relationship between factors that influence activity profile and technical performance during rotations in Australian football needs to be considered when interpreting match performance.

Factors Affecting Match Running Performance in Professional Australian Football.

PURPOSE: To examine the influence of a range of individual player characteristics and match-related factors on activity profiles during professional Australian football matches. METHODS: Global positioning system (GPS) profiles were collected from 34 professional Australian football players from the same club over 15 competition matches. GPS data were classified into relative total and high-speed running (HSR; >20 km/h) distances. Individual player aerobic fitness was determined from a 2-km time trial conducted during the preseason. Each match was classified according to match location, season phase, recovery length, opposition strength, and match outcome. The total number of stoppages during the match was obtained from a commercial statistics provider. A linear mixed model was constructed to examine the influence of player characteristics and match-related factors on both relative total and HSR outputs. RESULTS: Player aerobic fitness had a large effect on relative total and HSR distances. Away matches and matches lost produced only small reductions in relative HSR distances, while the number of rotations also had a small positive effect. Matches won, more player rotations, and playing against strong opposition all resulted in small to moderate increases in relative total distance, while early season phase, increased number of stoppages, and away matches resulted in small to moderate reductions in relative total distance. CONCLUSIONS: There is a likely interplay of factors that influence running performance during Australian football matches. The results highlight the need to consider a variety of contextual factors when interpreting physical output from matches.

Match score affects activity profile and skill performance in professional Australian Football players.

OBJECTIVES: To examine the influence of quarter outcome and the margin of the score differential on both the physical activity profile and skill performance of players during professional Australian Football matches. DESIGN: Prospective, longitudinal. METHODS: Physical activity profiles were assessed via microtechnology (Global Positioning System and accelerometer) from 40 professional AF players from the same team during 15 Australian Football League games. Skill performance measures (involvement and effectiveness) and player rank scores (Champion Data(©) Rank) were provided by a commercial statistical provider. The physical performance variables, skill involvements and individual player performance scores were expressed relative to playing time for each quarter. The influence of the quarter result (i.e. win vs. loss) and score margin (i.e. small: <9 points, moderate: 10-18 points, and large: >19 points) on activity profile and skill involvements and skill efficiency performance of players were examined. RESULTS: Skill involvements (total disposals/min, long kicks/min, marks/min, running bounces/min and player rank/min) were greater in quarters won (all p<0.01). In contrast, the players high speed running distance per minute (>14.5 km h(-1), HSR/min), sprints/min and peak speed were higher in losing quarters (all p<0.01). Smaller score margins were associated with increased physical activity (m/min, HSR/min, and body load/min, all p<0.05) and decreased skill efficiency (handball clangers/min and player rank/min, all p<0.05). CONCLUSIONS: Professional AF players are likely to have an increased physical activity profile and decreased skill involvement and proficiency when their team is less successful.

Factors affecting match performance in professional Australian football.

OBJECTIVES: To determine the physical activity measures and skill-performance characteristics that contribute to coaches' perception of performance and player performance rank in professional Australian Football (AF). DESIGN: Prospective, longitudinal. METHODS: Physical activity profiles were assessed via microtechnology (GPS and accelerometer) from 40 professional AF players from the same team during 15 Australian Football League games. Skill-performance measure and player-rank scores (Champion Data Rank) were provided by a commercial statistical provider. The physical-performance variables, skill involvements, and individual player performance scores were expressed relative to playing time for each quarter. A stepwise multiple regression was used to examine the contribution of physical activity and skill involvements to coaches' perception of performance and player rank in AF. RESULTS: Stepwise multiple-regression analysis revealed that 42.2% of the variance in coaches' perception of a player's performance could be explained by the skill-performance characteristics (player rank/min, effective kicks/min, pressure points/min, handballs/min, and running bounces/ min), with a small contribution from physical activity measures (accelerations/min) (adjusted R2 = .422, F6,282 = 36.054, P < .001). Multiple regression also revealed that 66.4% of the adjusted variance in player rank could be explained by total disposals/min, effective kicks/min, pressure points/min, kick clangers/min, marks/min, speed (m/min), and peak speed (adjusted R2 = .664, F7,281 = 82.289, P < .001). Increased physical activity throughout a match (speed [m/min] ß - 0.097 and peak speed ß - 0.116) negatively affects player rank in AF. CONCLUSIONS: Skill performance rather than increased physical activity is more important to coaches' perception of performance and player rank in professional AF.

Match running performance in elite Australian Rules Football.

There is little information describing the match running demands of elite-level Australian Rules Football (AF). The aims of this study were to examine: (1) match running demands; and (2) the influence of periods of increased physical activity on subsequent running performance in the Australian Football League. Time-motion analyses were performed 1-9 times per player from 16 professional AF players from the same club during games in 2005-2007, using portable global positioning systems during 65 matches. Game movements (standing, walking, jogging, running, higher-speed running, and sprinting) and distances (total distance covered [TD]; low-intensity activity [LIA, distance <14.4kmh(-1)]; and, high-intensity running distance [HIR, distance>14.4kmh(-1)]) were collected. The influence of the first half physical activities on second half activities, and each quarter on the subsequent quarter were analysed. The mean (+/-SD) TD and HIR distance covered during the games were 12,939+/-1145m and 3880+/-663m respectively. There were reductions in TD in the second (-7.3%), third (-5.5%) and fourth (-10.7%) quarters compared to the first quarter (p<0.01). The HIR was reduced after the first quarter (p<0.001). Players that covered larger TD or HIR during the first half or quarter decreased distance in the next half and quarter, respectively (p<0.001). These results show that a reduction in exercise intensity is inevitable during an AF match and that higher intensity activities reduce towards the end of games. High average speed during each half or quarter also affects subsequent running performance in elite-level AF.