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

Abstract

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.

Causal inference did not detect any effect of jump load on knee complaints in elite men's volleyball

“…Despite a larger sample size compared with those typical in training load studies 16 and use of a specific training load and injury definition that is biomechanically linked, no association was found between jump load and risk of knee complaints in elite, male volleyball players. A previous study, with comparable population and training load and injury definitions to this study, also struggled to detect a clear relationship between jump load and knee complaints 36 . This highlights the complex relationship between training load and changing injury complaints.…”

“…Damji et al 36 ,. who also measured jump load with the VERT device ( n = 12 players), found no association between jump load ACWR and increased knee pain in male elite volleyball players.…”

“…34 Our approach was modeling acute (weekly jump load) and chronic loads (past jump load) as separate variables in the same model. 35 Damji et al 36 , who also measured jump load with the VERT device (n = 12 players), found no association between jump load ACWR and increased knee pain in male elite volleyball players. Since the ACWR adjusts the acute load to the chronic load without handling potential nonlinearity in the chronic load, it may have led to the same result of no association as in our study.…”

“…A previous study, with comparable population and training load and injury definitions to this study, also struggled to detect a clear relationship between jump load and knee complaints. 36 This highlights the complex relationship between training load and changing injury complaints. Future studies may want to consider collecting complaints daily, rather than weekly.…”