Rates and risk factors of injury in CrossFit™: a prospective cohort study

BACKGROUND. CrossFit (TM) is a strength and conditioning program that has gained widespread popularity since its inception approximately 15 years ago. However, at present little is known about the level of injury risk associated with this form of training. Movement competency, assessed using the Functional Movement Screen (TM) (FMS), has been identified as a risk factor for injury in numerous athletic populations, but its role in CrossFit participants is currently unclear. The aim of this study was to evaluate the level of injury risk associated with CrossFit training, and examine the influence of a number of potential risk factors (including movement competency). METHODS. A cohort of 117 CrossFit participants were followed prospectively for 12 weeks. Participants' characteristics, previous injury history and training experience were recorded at baseline, and an FMS assessment was conducted. RESULTS. The overall injury incidence rate was 2.10 per 1000 training hours (90% confidence limits: 1.32-3.33). A multivariate Poisson regression model identified males (rate ratio [RR]: 4.44 x/divided by 3.30, very likely harmful) and those with previous injuries (RR: 2.35 x/divided by 2.37, likely harmful) as having a higher injury risk. Inferences relating to FMS variables were unclear in the multivariate model, although number of asymmetries was a clear risk factor in a univariate model (RR per two additional asymmetries: 2.62 x/divided by 1.53, likely harmful). CONCLUSIONS. The injury incidence rate associated with CrossFit training was low, and comparable to other forms of recreational fitness activities. Previous injury and gender were identified as risk factors for injury, whilst the role of movement competency in this setting warrants further investigation.