Assessing acute:chronic workload ratio methodologies for the prediction of knee pain in men's elite volleyball

Predicting sports injuries is a complex phenomenon given the multitude of risk factors involved and the need for an inciting event. Recent evidence suggests that the acute:chronic workload ratio (ACWR) is a potentially useful tool for quantifying athlete workloads, with athletes at increased risk of injury when the ACWR is higher relative to a lower ACWR. While several team sports have been studied in the ACWR literature, there is a paucity of studies that focus on volleyball athletes, and no studies that use knee pain as an outcome. Furthermore, controversy exists as inconsistent results among studies may be attributed to differences in calculating the ACWR. Our objective was to assess different definitions of the ACWR for predicting knee pain in elite volleyball athletes. We expected to see agreement with the literature in that ACWR would be positively associated with knee pain. We conducted a retrospective, exploratory analysis on a data set from a University varsity volleyball team. Our mixed effect modeling indicated that the coefficient estimates for the ACWR variants were small and statistically insignificant. The variant used did not have a major influence on the relationship with knee pain score, and the strength of the relationship was weak.