Letter to the Editor.

Dear Editor:

Our research group is currently conducting a systematic review and meta-analysis to, among other things, estimate the total injury incidence rate per 1000 hours of CrossFit training. In this process we have located the retrospective survey paper by Aune and Powers.[1]

The authors reported an injury incidence of 2.71 injuries per 1000 hours of exposure (2.87 and 2.62 for women and men, respectively). As I tried to replicate the results, I found that the injury incidence were only similar on the decimals.

Among others, a methodological paper by Phillips[4],[5](p674) has suggested to calculate and express the incidence rate (IR) per 1000 hours as:

To calculate the total incidence rate per 1000 hours of exposure using the results from Aune and Powers,[1] the calculation would look like this:

The reported and calculated injury incidence rates per 1000 hours of exposure are presented in Table 1. It seems that Aune and Powers have added 1.00 to the injury incidence. Consequently, I have been able to replicate the findings of other studies using the above-stated methodology.[2,3] Hence, it seems that Aune and Powers have made a systematic calculation error. I suggest that Aune and Powers recalculate their injury incidence and provide an update of the paper.

Table 1.

Calculations based on the formula by Phillips[4]

Group	Reported Injuries, n	Reported Participants, n	Reported Mean Hours of Exposure	Reported Injury Incidence per 1000 Hours of Exposure	Calculated Injury Incidence per 1000 Hours of Exposure
Total	85	247	200.6	2.71	1.72
Men	52	142	225.4	2.62	1.62
Women	33	105	167.4	2.87	1.88