Comparison of player-dependent and player-independent external workload thresholds to model injury risk in football

Abstract

Injury within team sports is a major concern of practitioners, athletes and sporting teams. Injuries have the potential to cost both economically in terms of rehabilitation but also cost success within competitive leagues. Indirect injuries are the major source of this burden within football, and have been shown to have manageable risk factors, such as training load and recovery strategies. The implementation of global positioning systems (GPS) into team sports allows for external workload tracking for individual players, during both training sessions and competitive matches. Typically, the method of tracking workload utilises the use of speed thresholds that are arbitrary and independent of player fitness characteristics. It has been shown that athletes completing the same external workload may experience vastly differing internal loads. Therefore, external workload tracking that is more sensitive to individual player fitness may improve workload tracking and provide greater insight into the dose-response of athletes. This aim of this thesis was to determine if individualising speed thresholds to player fitness could better model injury risks with semi-professional footballing populations. By following 33 outfield players from two separate clubs over the period of a whole season, workloads were analysed using both arbitrary and individualised speed thresholds and compared to indirect injury incidence. When utilised within a 7-28 day acute: chronic workload ratio, individualised speed thresholds accounting for total distance covered at very high speed (>MAS) demonstrated a very likely harmful effect (RR=1.94, 90%CI 1.14-3.32, p=0.042) when the ratio was =1.25. The equivalent arbitrary speed thresholds found no clear effects. Therefore, the results of this thesis indicate individualising speed thresholds may provide practitioners with greater insights into injury risk than arbitrary thresholds alone.

Date of Award	2017
Original language	English