Wheelchair rugby: Fast activity and performance analysis

Post-match wheelchair rugby performance analysis is currently confined to single parameters (e.g. distance, average speed, activity time) without presenting the change of these parameters with time in the course of a match. The aim of this study is to determine a single activity parameter, which represents the instantaneous performance and which serves for comparing the performance between different players, as well as to develop a method which is relatively cheap and ubiquitously applicable. A rugby wheelchair was instrumented with an accelerometer (iPhone by Apple) and data were collected while pushing at all of the four combinations of high/low acceleration and high/low frequency. These four combinations were assigned performance ranks from 1 to 4, and the following activity parameters were determined: mean acceleration amplitude, mean stroke frequency, and the Hausdorff (fractal) dimension. The Hausdorff dimension correlated highly with the mean acceleration amplitude, mean frequency and performance rank as well as with the product of frequency and amplitude. The Hausdorff dimension of the signal is suitable to replace and represent conventional performance parameters.