The Association Between the Acute:Chronic Workload Ratio and Injury and its Application in Team Sports: A Systematic Review.
Level 3 - non-randomized controlled study
Systematic review of non-randomized observational cohort studies
PubMed 31691167 · doi:10.1007/s40279-019-01218-2
What was done
A systematic review was conducted across EMBASE, Medline, SPORTDiscus, SCOPUS, AMED, and CINAHL to assess the association between the acute:chronic workload ratio (ACWR)—calculated via rolling average (RA) or exponentially weighted moving average (EWMA) models—and injury occurrence in team sports. Study quality was evaluated using the Newcastle-Ottawa Scale (NOS) for cohort studies.
What was found
Twenty-two articles were included, with an overall median NOS quality score of 8 (range 5–9). The findings supported an association between ACWR and non-contact injuries. While both RA and EWMA models had supportive evidence, EWMA was identified as the more suitable metric due to higher sensitivity. Optimal acute and chronic time periods and load metrics varied by sport. No numerical effect sizes, relative risks, or pooled statistics were reported in the abstract.
Why it matters
This review supports ACWR as a valid monitoring component within comprehensive athlete management systems to mitigate non-contact injury risk, highlighting EWMA as the preferred calculation method.
Limits
The abstract reports no quantitative pooled risk estimates or hazard ratios. The underlying evidence relies entirely on observational cohort designs with substantial heterogeneity across sports, sexes, workload parameters, and tracking timeframes.
Cited by
- supports Drastic increases in training volume or load without proper preparation are major risk factors for acute injury.