Player acceleration and deceleration profiles in professional Australian football.

This study aimed to determine the validity and reliability of global positioning system (GPS) units for measuring a standardized set of acceleration and deceleration zones and whether these standardized zones were capable of identifying differences between playing positions in professional Australian football. Eight well trained male participants were recruited to wear two 5 Hz or 10 Hz GPS units whilst completing a team sport simulation circuit to measure acceleration and deceleration movements. For the second part of this article 30 professional players were monitored between 1-29 times using 5 Hz and 10 Hz GPS units for the collection of acceleration and deceleration movements during the 2011 and 2012 Australian Football League seasons. Players were separated into four distinct positional groups - nomadic players, fixed defenders, fixed forwards and ruckman. The GPS units analysed had good to poor levels of error for measuring the distance covered (<19.7%), time spent (<17.2%) and number of efforts performed (<48.0%) at low, moderate and high acceleration and deceleration zones. The results demonstrated that nomadic players and fixed defenders perform more acceleration and deceleration efforts during a match than fixed forwards and ruckman. These studies established that these GPS units can be used for analysing the distance covered and time spent at the acceleration and deceleration zones used. Further, these standardized zones were proven to be capable of distinguishing between player positions, with nomadic players and fixed defenders required to complete more high acceleration and deceleration efforts during a match.