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.