Position specific peak running demands, and influence of bout type in professional rugby union

Objectives: 

To quantify peak running intensity in professional rugby union across position groups, and peak running intensity differences between bout types (i.e., whole, starter, substitute). 

Design:

Longitudinal study. 

Method:

Global positioning systems were used to assess the activity of 36 professional rugby union players. A moving average approach was used to identify the 1- to 10-minute peak intensity period distances, and time spent above 80% and 90% of individual 1-minute match peak. Differences between position groups and bout type were determined by magnitude-based inferences. 

Results:

All position groups showed most likely moderate to most likely large differences in peak intensity periods, except for tight 5 vs. backrow (possibly trivial small and possibly small), and half-backs vs. outside backs (very likely trivial small to likely trivial small). No position group comparison for time spent above 80% and 90% of 1-minute match peak resulted in moderate or greater differences. Possibly moderate to most likely moderate difference were observed between forwards whole vs. forward substitutes in 2- to 10-minute peak periods; most likely moderate differences were observed between forwards starters vs. forward substitutes in 10-minute peak intensity period; and most likely moderate differences were observed between backs whole vs. backs substitutes in the 1-minute peak intensity period. For time spent above 80% and 90% of 1-minute match peak all bout type comparisons resulted in most likely moderate to most likely large differences. 

Conclusions:

There are meaningful differences between position groups in peak running intensity in professional rugby union, and substitute players perform lower peak intensity running than whole or starters.