An integrated measurement system for analysing impact biomechanics in the rugby scrum

As part of a wider project investigating the biomechanics of the rugby scrum within rugby union, the focus of the present study was to design, realise and test an unobtrusive measurement system for assessing the kinematics and kinetics of rugby forwards while scrummaging on the pitch in realistic environmental conditions. Currently the study investigates one forward pack (eight players) scrummaging against an instrumented scrum machine, a training aid used widely throughout rugby. The measurement system integrates three different subsystems for: (1) measuring forces exerted by players; (2) capturing players' movements; and, (3) triggering/synchronising all the sensors involved in (1) and (2). Applied three-dimensional forces were measured by strain gauge circuits attached to each pusher arm of the machine and then summed to produce the components of overall force. Multiple camera views allowed the recording and subsequent analysis of player movements, in the primary transverse (50 Hz and 200 Hz) and sagittal (50 Hz) planes of motion. A control system executed pre-recorded audio commands to players with consistent timings, sent trigger pulses to acquisition devices and collected analogue data at 500 Hz. The overall system has been applied successfully in the field to record data from rugby union forward packs across a range of playing levels and initial results confirm that the measurement system will be useful for its desired purpose to compare the biomechanics of different scrum engagement techniques.