Anthea C. Clarke

Stability of athlete passport parameters during extended storage

Extended intervals between sample collection and analyses render athletes whole‐blood specimens collected in the field for antidoping purposes susceptible to storage degradation. The aim of this study was to characterize the stability of key blood variables under different storage durations and temperatures.

Physiologically based GPS speed zones for evaluating running demands in Women's Rugby Sevens

Abstract High-speed running (>5 m · s−1) is commonly reported in men’s rugby union and sevens; however, the appropriateness of using the same speed threshold for Women’s Rugby Sevens players is unclear, and likely underestimates the degree of high-intensity exercise completed by female players. The aim of this study was to establish, for international Women’s Rugby Sevens players, a physiologically defined threshold – speed at the second ventilatory threshold (VT2speed) – for the analysis of high-intensity running, using mean and individualised thresholds. Game movement patterns (using 5 Hz GPS) of 12 international Women’s Rugby Sevens players (23.5 ± 4.9 years, 1.68 ± 0.04 m, 68.2 ± 7.7 kg; mean ± s) were collected at an international tournament. Seven of these players also completed a treadmill VO2max test to estimate VT2speed. Compared to the mean VT2speed threshold (3.5 m · s−1), the industry-used threshold of 5 m · s−1 underestimated the absolute amount of high-intensity running completed by individual players by up to 30%. Using an individualised threshold, high-intensity running could over- or underestimating high-intensity running by up to 14% compared to the mean VT2speed threshold. The use of individualised thresholds provides an accurate individualised assessment of game demands to inform the prescription of training.

Critical velocity as a measure of aerobic fitness in women's rugby sevens

OBJECTIVES To compare a field-based critical velocity running test to routine laboratory (treadmill VO₂ max test) and field-based (Yo-Yo intermittent recovery test, Yo-Yo IR1) aerobic fitness tests in womens rugby sevens (7s) players. To quantify the degree of association between field-based fitness test scores and GPS-derived analysis of performance data in competition. DESIGN Single cohort, cross-sectional study involving 22 female Australian Rugby 7s National team players. METHODS Players underwent fitness testing comparing the critical velocity test (100 m, 400 m, 1500 m runs) to the Yo-Yo IR1 and a treadmill VO₂ max test. GPS data was obtained during the National Championships using a subgroup of 12 players and compared with each players fitness test scores. RESULTS The critical velocity test was highly correlated with the Yo-Yo IR1 test (r=0.86, 0.69-0.94; 90% confidence interval) and all variables of the VO₂ max test, however mean values were substantially different between tests (Yo-Yo IR1: 4.3 ± 0.1 ms(-1), vVO₂ max: 3.7 ± 0.3 ms(-1), critical velocity: 3.2 ± 0.3 ms(-1)). Average speed, obtained from GPS data, was largely correlated with both the Yo-Yo IR1 (r=0.62, 0.10-0.87) and critical velocity (r=0.51, -0.06-0.83) tests. Total game distance correlated moderately with the Yo-Yo IR1 (r=0.49, -0.09-0.82) and critical velocity (r=0.36, -0.25-0.76). CONCLUSIONS The critical velocity test is an appropriate aerobic fitness test, yields results similar to the Yo-Yo IR1, and correlates moderately with rugby 7s game data. However the Yo-Yo IR1 and critical velocity test scores cannot be used interchangeably.

Neuromuscular Fatigue and Muscle Damage After a Women’s Rugby Sevens Tournament

PURPOSE To examine relationships between on-field game movement patterns and changes in markers of neuromuscular fatigue and muscle damage during a 2-d womens rugby sevens tournament. METHODS Female national (mean ± SD n = 12, 22.3 ± 2.5 y, 1.67 ± 0.04 m, 65.8 ± 4.6 kg) and state (n = 10, 24.4 ± 4.3 y, 1.67 ± 0.03 m, 66.1 ± 7.9 kg) representative players completed baseline testing for lower-body neuromuscular function (countermovement-jump [CMJ] test), muscle damage (capillary creatine kinase [CK]), perceived soreness, and perceived recovery. Testing was repeated after games on days 1 and 2 of the tournament. GPS (5-Hz) data were collected throughout the tournament (4-6 games/player). RESULTS National players were involved in greater on-field movements for total time, distance, high-speed running (>5 m/s), and impacts >10 g (effect size [ES] = 0.55-0.97) and displayed a smaller decrement in performance from day 1 to day 2. Despite this, state players had a much greater 4-fold increase (δCK = 737 U/L) in CK compared with the 2-fold increase (δCK = 502 U/L) in national players (ES = 0.73). Both groups had similar perceived soreness and recovery while CMJ performance was unchanged. High-speed running and impacts >10 g were largely correlated (r = .66-.91) with δCK for both groups. CONCLUSION A 2-day womens rugby sevens tournament elicits substantial muscle damage; however, there was little change in lower-body neuromuscular function. Modest increases in CK can largely be attributed to high-speed running and impacts >10 g that players typically endure.

Preanalytical mixing of whole-blood specimens in the context of the Athlete Passport

Background Full blood counts are now used as evidence that athletes have used banned blood doping. This has led to legal scrutiny of the efficacy of preanalytical procedures such as specimen homogenisation. Aims To characterise the impact of different mixing strategies on whole-blood homogeneity. Methods Manual inversion, mechanical mixing and automatic mixing performed by the Sysmex XT-2000i were evaluated. Results Automated mixing by the instrument, or 1 min of mechanical mixing, thoroughly homogenised specimens even for tubes that had been refrigerated and left undisturbed for 36 h. Manual inversions were almost as effective, provided that specimens were first allowed to equilibrate to ambient temperatures. Conclusions Current sport guidelines that mandate at least 15 min of mechanical mixing are excessive. Except where specimens are presented to the instrument manually, mechanical mixing is redundant in the context of full blood counts.

Game movement demands and physical profiles of junior, senior and elite male and female rugby sevens players

ABSTRACT To inform recruitment, selection, training and testing of male and female rugby sevens players game running movement patterns and physical characteristics were quantified across junior, senior, and elite playing levels. Anthropometric and physical testing (40 m sprint, vertical jump, Yo-Yo IR1) occurred prior to players’ national championships or international tournaments (n = 110 players), while game movements were obtained via GPS (n = 499 game files). The game movements of male players were similar across playing levels except for number of impacts >10 g which were 2 to 4-fold higher in elite (25.0 ± 11.2 impacts · game−1; mean ± SD), than junior (6.3 ± 3.5) and senior (11.8 ± 6.6) players. In men, there were fewer substantial correlations between on- and off-field measures which may reflect similar physical attributes across playing levels, and that other (strength, technical or tactical) factors may better differentiate these players. In females, elite players had more favourable on- and off-field performance measures than juniors and seniors, with moderate to strong correlations between on- and off-field variables. Female players should benefit from additional fitness training, while male players need to balance fitness with other technical and tactical factors.

Proof of concept of automated collision detection technology in rugby sevens.

Abstract Clarke, AC, Anson, JM, and Pyne, DB. Proof of concept of automated collision detection technology in rugby sevens. J Strength Cond Res 31(4): 1116–1120, 2017—Developments in microsensor technology allow for automated detection of collisions in various codes of football, removing the need for time-consuming postprocessing of video footage. However, little research is available on the ability of microsensor technology to be used across various sports or genders. Game video footage was matched with microsensor-detected collisions (GPSports) in one mens (n = 12 players) and one womens (n = 12) rugby sevens match. True-positive, false-positive, and false-negative events between video and microsensor-detected collisions were used to calculate recall (ability to detect a collision) and precision (accurately identify a collision). The precision was similar between the mens and womens rugby sevens game (∼0.72; scale 0.00–1.00); however, the recall in the womens game (0.45) was less than that for the men’s game (0.69). This resulted in 45% of collisions for men and 62% of collisions for women being incorrectly labeled. Currently, the automated collision detection system in GPSports microtechnology units has only modest utility in rugby sevens, and it seems that a rugby sevens–specific algorithm is needed. Differences in measures between the mens and womens game may be a result of physical size, and strength, and physicality, as well as technical and tactical factors.

Physical demands and technical performance in Australian Football League Women’s (AFLW) competition match-play

OBJECTIVES To compare positional differences in the physical and technical demands of Australian Football League Womens (AFLW) match-play. A secondary aim was to examine the time course changes in activity profiles during AFLW match-play. DESIGN Longitudinal observational study. METHODS Global positioning system data were collected from 26 players (6 positional groups) from the same club during seven AFLW matches. Absolute and relative physical performance data were categorised into total distance, high-speed running (>14.4kmh-1, HSR), very high-speed running (>18.0kmh-1, VHSR), and sprinting distance (>20.0kmh-1, Sprint). Technical performance data was obtained from a commercial statistics provider. A mixed model analysis was used to examine differences between positional groups and playing quarters. RESULTS Absolute measures of running performance did not differ between position groups. Relative total distance was moderately greater (ES=∼0.80, p<0.05) for midfielders, small backs and small forwards (125-128mmin-1) than tall backs and tall forwards (102-107mmin-1). Relative HSR distance was greater (ES=∼0.73) for midfielders and small backs (∼28mmin-1) than tall backs (17mmin-1). Analysis of technical performance indicators showed: midfielders and small forwards had the most inside 50s; tall backs had the highest number of rebound 50s; tall forwards scored more goals; while midfielders made more tackles (p<0.05). All relative running performance measures were reduced in the fourth quarter when compared to the first and second quarters (ES=0.32-0.77). CONCLUSIONS These data can be used as benchmarks for temporal analysis of AFLW match demands and assist in developing specific training strategies.

Comparison of the match running demands of elite and sub-elite women’s Australian Football

ABSTRACT Objectives: This study aimed to quantify and compare the match running movements of elite (AFLW) and sub-elite (VFLW) women’s Australian Football (AF) competitions. Methods: Match running movements (GPS) were recorded during 7 AFLW (n = 91 files) and 13 VFLW (n = 263 files) competition matches. Results: AFLW players covered moderately greater relative high-speed running (HSR, 14.4–18.0 km·h−1, AFLW 14.9 ± 5.7 m·min−1; VFLW 12.2 ± 3.9 m·min−1; ES = 0.61, ±0.39), very high-speed running (VHSR, 18.0–20.0 km·h−1, 4.2 ± 2.0 m·min−1; 3.2 ± 1.4 m·min−1; ES = 0.61, ±0.14), and sprint (>20 km·h−1, 3.3 ± 2.2 m·min−1; 2.1 ± 1.6 m·min−1; ES = 0.65, ±0.16) distances than VFLW players. Small to large differences were apparent within positions between competitions for HSR, VHSR, and sprint distances, most notably in small forwards (ES = 0.78–1.45). VHSR and sprint distances decreased in the fourth quarter when compared with quarters one and two (ES = 0.22–0.33) in the AFLW competition, whereas VFLW match running movements remained consistent across quarters. Conclusions: These differences may reflect the variations in match rules between competitions (fewer on-field players and shorter match time in AFLW), providing greater on-field space per player and interchange frequency. This information can assist in prescribing appropriate training for women’s AF competition.