When previous wear time compliance results are taken together with our findings, it represents a promising step forward for monitoring and understanding 24-h time-use behaviors. The next step will be to examine the generalizability of these findings in a free-living setting.

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Measurements of isometric force, rate of force development (RFD) and impulse are widely reported. However, little is known about the variability and reliability of these measurements at multiple angles, over repeated testing occasions in a homogenous, resistance-trained population. Thus, understanding the intersession variability of multi-angle isometric force-time characteristics provides the purpose of this paper. Three sessions of isometric knee extensions at 40º, 70º and 100º of flexion were performed by 26 subjects across 51 limbs. All assessments were repeated on three occasions separated by 5-8 days. Variability was qualified by doubling the typical error of measurement (TEM), with thresholds of 0.2-0.6 (small), 0.6-1.2 (moderate), 1.2-2.0 (large), 2.0-4.0 (very large) and >4.0 (extremely large). Additionally, variability was deemed large when the intraclass correlation coefficient (ICC) was <0.67 and coefficient of variation (CV)>10%; moderate when ICC>0.67 or CV<10% (but not both); and small when both ICC>0.67 and CV<10%. Small to moderate between-session variability (ICC=0.68-0.95, CV=5.2-18.7%, TEM=0.24-0.49) was associated with isometric peak force, regardless of angle. Moderate to large variability was seen in early-stage (0-50 ms) RFD and impulse (ICC=0.60-0.80, CV=22.4-63.1%, TEM=0.62-0.74). Impulse and RFD at 0-100 ms, 0-200 ms and 100-200 ms were moderately variable (ICC=0.71-0.89, CV=11.8-42.1%, TEM=0.38-0.60) at all joint angles. Isometric peak force and late-stage isometric RFD and impulse measurements were found to have low intersession variability regardless of joint angle. However, practitioners need to exercise caution when making inferences about early-stage RFD and impulse measures due to moderate-large variability.

Play based sports monitoring techniques provide coaches and players with the tools to better measure the effects of training or live performance. This paper explores the advantages of using accelerometers units, in an effort to better analyse over ground running in professional athletes. A large portion of studies in player monitoring in the Australian Football League (AFL) utilize GPS to obtain time and distance measurements.Previous studies have shown that the speed and energy expenditure of an athlete while running on a treadmill can be obtained through the use of body mounted accelerometers. This research extends these concepts by applying them to overground running data from professional players.A study was conducted using professional AFL players and GPS and accelerometer sensors. The data obtained was filtered and the stride frequency was obtained for stepwise bands of constant running speed between 4km/h and 24km/h. Stride frequency was compared to speed obtained from the GPS. A linear relationship between stride frequency and speed was identified and agreed with the literature. This indicates that a player's speed can be approximately derived from their stride frequency, and thus, more efficient and cost effective accelerometer can be used in lieu of GPS units.