The ball in play demands of international rugby union.

OBJECTIVES: Rugby union is a high intensity intermittent sport, typically analysed via set time periods or rolling average methods. This study reports the demands of international rugby union via global positioning system (GPS) metrics expressed as mean ball in play (BiP), maximum BiP (max BiP), and whole match outputs.

DESIGN: Single cohort cross sectional study involving 22 international players, categorised as forwards and backs.

METHODS: A total of 88 GPS files from eight international test matches were collected during 2016. An Opta sportscode timeline was integrated into the GPS software to split the data into BiP periods. Metres per min (mmin-1 ), high metabolic load per min (HML), accelerations per min (Acc), high speed running per min (HSR), and collisions per min (Coll) were expressed relative to BiP periods and over the whole match (>60min).

RESULTS: Whole match metrics were significantly lower than all BiP metrics (p<0.001). Mean and max BiP HML, (p<0.01) and HSR (p<0.05) were significantly higher for backs versus forwards, whereas Coll were significantly higher for forwards (p<0.001). In plays lasting 61s or greater, max BiP mmin-1 were higher for backs. Max BiP mmin-1 , HML, HSR and Coll were all time dependant (p<0.05) showing that both movement metrics and collision demands differ as length of play continues.

CONCLUSIONS: This study uses a novel method of accurately assessing the BiP demands of rugby union. It also reports typical and maximal demands of international rugby union that can be used by practitioners and scientists to target training of worst-case scenario's equivalent to international intensity. Backs covered greater distances at higher speeds and demonstrated higher HML, in general play as well as 'worst case scenarios'; conversely forwards perform a higher number of collisions.