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Robert J. Aughey

Previous research has suggested elite Australian footballers undertake pacing strategies to preserve high intensity activity later in matches. However, this research used GPS with slow sample rates, did not express performance relative to minutes played during games and used lowly ranked players.

Methods:

Therefore in this study movement was recorded by GPS at 5 Hz. Running performance was expressed per period of the match (rotation) divided into low-intensity activity (LIA, 0.10 to 4.17 m⋅s–1); high-intensity running (HIR, 4.17 to 10.00 m⋅s–1) and maximal accelerations (2.78 to 10.00 m⋅s–2). All data were expressed relative to the first period of play in the match and the magnitude of effects was analyzed with the effect size (ES) statistic and expressed with confidence intervals.

Results:

The total and LIA distance covered by players did not change by a practically important magnitude during games (ES< 0.20). High intensity running was reduced in both rotations of the second quarter, Q3R2 and both rotations of the fourth quarter (ES -0.30 ± 0.14; -0.42 ± 0.14; -0.30 ± 0.14; -0.42 ± 0.14; and -0.48 ± 0.15 respectively). Maximal acceleration performance was reduced in Q1R2, and each rotation of the second half of matches.

Conclusion:

When expressed per minute of game time played, total distance and low intensity activity distance are not reduced by a practically important magnitude in AF players during a match. These data are therefore inconsistent with the concept of team sport players pacing their effort during matches. However, both high intensity running and maximal accelerations are reduced later in games, indicative of significant fatigue in players.

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Conor M. Bolger, Jan Kocbach, Ann Magdalen Hegge and Øyvind Sandbakk

Purpose:

To compare the speed and heart-rate profiles during international skating and classical competitions in male and female world-class cross-country skiers.

Methods:

Four male and 5 female skiers performed individual time trials of 15 km (men) and 10 km (women) in the skating and classical techniques on 2 consecutive days. Races were performed on the same 5-km course. The course was mapped with GPS and a barometer to provide a valid course and elevation profile. Time, speed, and heart rate were determined for uphill, flat, and downhill terrains throughout the entire competition by wearing a GPS and a heart-rate monitor.

Results:

Times in uphill, flat, and downhill terrain were ~55%, 15–20%, and 25–30%, respectively, of the total race time for both techniques and genders. The average speed differences between skating and classical skiing were 9% and 11% for men and women, respectively, and these values were 12% and 15% for uphill, 8% and 13% for flat (all P < .05), and 2% and 1% for downhill terrain. The average speeds for men were 9% and 11% faster than for women in skating and classical, respectively, with corresponding numbers of 11% and 14% for uphill, 6% and 11% for flat, and 4% and 5% for downhill terrain (all P < .05). Heart-rate profiles were relatively independent of technique and gender.

Conclusions:

The greatest performance differences between the skating and classical techniques and between the 2 genders were found on uphill terrain. Therefore, these speed differences could not be explained by variations in exercise intensity.

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Billy T. Hulin, Tim J. Gabbett, Simon Kearney and Alex Corvo

Purpose:

To quantify activity profiles in approximately 5-min periods to determine if the intensity of rugby league match play changes after the most intense period of play and to determine if the intensity of activity during predefined periods of match play differ between successful and less-successful teams playing at an elite standard.

Methods:

Movement was recorded using a MinimaxX global positioning system (GPS) unit sampling at 10 Hz during 25 rugby league matches, equating to 200 GPS files. Data for each half of match play were separated into 8 equal periods. These periods represented the most intense phase of match play (peak period), the period after the most intense phase of match play (subsequent period), and the average demands of all other periods in a match (mean period). Two rugby league teams were split into a high-success and a low-success group based on their success rates throughout their season.

Results:

Compared with their less-successful counterparts, adjustables and hit-up forwards from the high-success team covered less total distance (P < .01) and less high-intensity-running distance (P < .01) and were involved in a greater number of collisions (P < .01) during the mean period of match play.

Conclusions:

Although a greater number of collisions during match play is linked with a greater rate of success, greater amounts of high-intensity running and total distance are not related to competitive success in elite rugby league. These results suggest that technical and tactical differences, rather than activity profiles, may be the distinguishing factor between successful and less-successful rugby league teams.

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Jakob Tarp, Lars B. Andersen and Lars Østergaard

Background:

Cycling to and from school is an important source of physical activity (PA) in youth but it is not captured by the dominant objective method to quantify PA. The aim of this study was to quantify the underestimation of objectively assessed PA caused by cycling when using accelerometry.

Methods:

Participants were 20 children aged 11 to 14 years from a randomized controlled trial performed in 2011. Physical activity was assessed by accelerometry with the addition of heart rate monitoring during cycling to school. Global positioning system (GPS) was used to identify periods of cycling to school.

Results:

Mean minutes of moderate-to-vigorous physical activity (MVPA) during round-trip commutes was 10.8 (95% CI: 7.1−16.6). Each kilometer of cycling meant an underestimation of 9314 (95% CI: 7719−11238) counts and 2.7 (95% CI: 2.1−3.5) minutes of MVPA. Adjusting for cycling to school increased estimates of MVPA/day by 6.0 (95% CI: 3.8−9.6) minutes.

Conclusions:

Cycling to and from school contribute substantially to levels of MVPA and to mean counts/min in children. This was not collected by accelerometers. Using distance to school in conjunction with self-reported cycling to school may be a simple tool to improve the methodology.

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Line Anita Bjørkelund Børrestad, Lars Østergaard, Lars Bo Andersen and Elling Bere

Background:

To provide more accurate assessment of commuting behavior and potential health effect, it is important to have accurate methods. Therefore, the current study aimed to a) compare questionnaire reported mode of commuting with objectively measured data from accelerometer and cycle computer, b) compare moderate vigorous physical activity (MVPA) among children cycling vs. walking to school, and c) thus calculate possible underestimated MVPA, when using accelerometers to measure commuter cycling.

Methods:

A total of 78 children, average age 11.4 (SD = 0.5), participated in the study. Physical activity was measured with cycle computers and accelerometers for 4 days. Mode of commuting and demographic information was self-reported in a questionnaire.

Results:

Children who reported to cycle to school spent significantly more time cycling than those who walked to school, 53.6 (SD = ± 33.9) minutes per day vs. 25.5 (SD = ± 24.6) minutes per day (P = .002) (ie, showing that MVPA, measured by accelerometers, underestimated 28.1 minutes per day among children cycling to school vs. those not cycling to school).

Conclusion:

To provide more accurate assessment of active commuting in children and adolescents future studies should incorporate multiple methodologies such as global position systems (GPS), accelerometers, cycle computers, and self-reported measurements.

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Louise Martin, Anneliese Lambeth-Mansell, Liane Beretta-Azevedo, Lucy A. Holmes, Rachel Wright and Alan St Clair Gibson

Purpose:

Given the paucity of research on pacing strategies during competitive events, this study examined changes in dynamic high-resolution performance parameters to analyze pacing profiles during a multiple-lap mountain-bike race over variable terrain.

Methods:

A global-positioning-system (GPS) unit (Garmin, Edge 305, USA) recorded velocity (m/s), distance (m), elevation (m), and heart rate at 1 Hz from 6 mountain-bike riders (mean ± SD age = 27.2 ± 5.0 y, stature = 176.8 ± 8.1 cm, mass = 76.3 ± 11.7 kg, VO2max = 55.1 ± 6.0 mL · kg−1 . min−1) competing in a multilap race. Lap-by-lap (interlap) pacing was analyzed using a 1-way ANOVA for mean time and mean velocity. Velocity data were averaged every 100 m and plotted against race distance and elevation to observe the presence of intralap variation.

Results:

There was no significant difference in lap times (P = .99) or lap velocity (P = .65) across the 5 laps. Within each lap, a high degree of oscillation in velocity was observed, which broadly reflected changes in terrain, but high-resolution data demonstrated additional nonmonotonic variation not related to terrain.

Conclusion:

Participants adopted an even pace strategy across the 5 laps despite rapid adjustments in velocity during each lap. While topographical and technical variations of the course accounted for some of the variability in velocity, the additional rapid adjustments in velocity may be associated with dynamic regulation of self-paced exercise.

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Sam Coad, Bon Gray and Christopher McLellan

Purpose:

To assess match-to-match variations in salivary immunoglobulin A concentration ([s-IgA]) measured at 36 h postmatch throughout an Australian Football League (AFL) premiership season and to assess the trends between 36-h-postmatch [s-IgA] and match-play exercise workloads throughout the same season.

Methods:

Eighteen elite male AFL athletes (24 ± 4.2 y, 187.0 ± 7.1 cm, 87.0 ± 7.6 kg) were monitored on a weekly basis to determine total match-play exercise workloads and 36-h-postmatch [s-IgA] throughout 16 consecutive matches in an AFL premiership season. Global positioning systems (GPS) with integrated triaxial accelerometers were used to measure exercise workloads (PlayerLoad) during each AFL match. A linear mixed-model analyses was conducted for time-dependent changes in [s-IgA] and player load.

Results:

A significant main effect was found for longitudinal postmatch [s-IgA] data (F 16,240 = 3.78, P < .01) and PlayerLoad data (F 16,66 = 1.98, P = .03). For all matches after and including match 7, a substantial suppression trend in [s-IgA] 36-h-postmatch values was found compared with preseason baseline [s-IgA].

Conclusion:

The current study provides novel data regarding longitudinal trends in 36-h-postmatch [s-IgA] for AFL athletes. Results demonstrate that weekly in-season AFL match-play exercise workloads may result in delayed mucosal immunological recovery beyond 36 h postmatch. The inclusion of individual athlete-monitoring strategies of [s-IgA] may be advantageous in the detection of compromised postmatch mucosal immunological function for AFL athletes.

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Mark Waldron, Jamie Highton and Craig Twist

Purpose:

This study assessed the reliability of a rugby league movement-simulation protocol, relative to interchanged players (RLMSP-i).

Methods:

Fifteen male participants completed 2 trials of the RLMSP-i, separated by 1 wk. The RLMSP-i comprised low- to moderate-intensity running, interspersed by high-intensity sprinting and tackling activity, based on global positioning system (GPS) data recorded during Super League performances.

Results:

The lowest coefficient of variation (CV ± 95% CI) was observed for total m/min during both interchange bout 1 (1.1% ± 0.2%) and bout 2 (1.0% ± 0.2%). The percentage of heart rate peak and ratings of perceived exertion demonstrated CVs of 1.2–2.0% and 2.9–3.5%, respectively. The poorest agreement between trials was found for blood lactate concentration (16.2% ± 2.8%). In no case was the CV smaller than the smallest worthwhile change, yet in every case the moderate changes were larger than the CV.

Conclusions:

The RLMSP-i’s reliability is sufficient to enable the detection of moderate changes in various performance and physiological measurements that accurately simulate some, but not all, aspects of rugby league matches.

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Sam Coad, Bon Gray, George Wehbe and Christopher McLellan

Purpose:

To examine the response or pre- and postmatch salivary immunoglobulin A concentration ([s-IgA]) to Australian Football League (AFL) match play and investigate the acute and cumulative influence of player workload and postmatch [s-IgA] after repeated participation in AFL match play.

Methods:

Eleven elite AFL athletes (21.8 ± 2.4 y, 186.9 ± 7.9 cm, 87.4 ± 7.5 kg) were monitored throughout 3 matches during the preseason that were separated by 7 d. Saliva samples were collected across each AFL match at 24 h and 1 h prematch and 1, 12, 36, and 60 h postmatch to determine [s-IgA]. Global positioning systems (GPS) with integrated triaxial accelerometers were used to determine total player workload during match play. Hypothesis testing was conducted for time-dependent changes in [s-IgA] and player load using a repeated-measures ANOVA.

Results:

Player load during match 3 (1266 ± 124.6 AU) was significantly (P < .01) greater than in match 1 (1096 ± 115.1 AU) and match 2 (1082 ± 90.4 AU). Across match 3, [s-IgA] was significantly (P < .01) suppressed at 2 postmatch measures (12 and 36 h) compared with prematch measures (24 and 1 h), which coincided with significantly (P < .01) elevated player load.

Conclusion:

The findings indicate that an increase in player load during AFL preseason match play resulted in compromised postmatch mucosal immunological function. Longitudinal assessment of AFL-match player load and mucosal immunological function across the first 60 h of recovery may augment monitoring and preparedness strategies for athletes.

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Timothy B. Hartwig, Geraldine Naughton and John Searl

Purpose:

Investigating adolescent training loads might help us understand optimal training adaptations. GPS tracking devices and training diaries were used to quantify weekly sport and other physical activity demands placed on adolescent rugby union players and profile typical rugby training sessions.

Methods:

Participants were 75 males age 14 to 18 y who were recruited from rugby teams representing 3 levels of participation: schoolboy, national representative, and a selective sports school talent squad.

Results:

Schoolboy players covered a distance of (mean ± SD) 3511 ± 836 m, representative-squad players 3576 ± 956 m, and talent-squad players 2208 ± 637 m per rugby training session. The representative squad recorded the highest weekly duration of sport and physical activity (515 ± 222 min/wk), followed by the talent squad (421 ± 211 min/week) and schoolboy group (370 ± 135 min/wk). Profiles of individual players identified as group outliers showed participation in up to 3 games and up to 11 training sessions per week, with twice the weekly load of the team averages.

Conclusion:

Optimal participation and performance of adolescent rugby union players might be compromised by many high-load, high-impact training sessions and games and commitments to other sports and physical activities. An improved understanding of monitoring and quantifying load in adolescent athletes is needed to facilitate best-practice advice for player management and training prescription.