Physical demands of elite Rugby League referees: Part one--time and motion analysis.

The purpose of the present study was to accurately and reliably analyse the nature of movement undertaken by National Rugby League (NRL) referees during matches played in the 2000 season. The movements of NRL referees (n=5) were analysed from videotape footage of ten games. The researchers assigned each movement to one of six defined categories (stationary, walking forwards, jogging forwards, sprinting, sideways, and backwards), and recorded number of repetitions, movement durations, and distances covered during each specific movement category. Distance was estimated using on-field markings as known points. Mean total distance per game was 6.7 km +/- 0.4 km (mean +/- standard deviation), and was made up of approximately 940 movements per game. The data showed 87% of distance was made up of a cyclic activity comprising jogging forwards, then backwards at mean running speeds of 7.2 km x h(-1) and 10.8 km x h(-1) respectively (made up of 9s bursts on average, each separated by 3s breaks). However, this cyclic activity accounted for only 47% of time, as referees were stationary 41% of time. Play was continuous for 90s +/- 71s at each phase of play, and was followed by rest of 45s +/- 36s throughout matches (work to rest ratio was 2:1). These findings suggest Rugby League refereeing is a highly intermittent activity and therefore training and fitness assessments should reflect these specific demands experienced during a game.