Analysing Recurrent Events in Exercise Science and Sports Medicine (Commentary) (Report‪)‬

Introduction Episodic or recurrent events are a class of data that is frequently described in sports medicine literature. However, the correct statistical techniques to deal with data containing recurrent events are not widely known within sports medicine and the exercise sciences. This is evidenced by the few papers in these specialist sciences that discuss the use of appropriate statistical techniques (1,2) and the preponderance of papers assuming event independence for recurrent events. For instance, in a recent paper (3) it is apparent that there is a trend in studies reporting injury incidences in rugby union players that need to be highlighted, namely the use of naive statistical methods that treat recurrent events as independent observations. A number of references are cited (see (3) ref. 2, 11, 15-17) that also report injury incidence statistics in rugby union players, and as far as can be ascertained, treat recurrent or multiple injuries within the same individual as independent events. The purpose of this paper was first, on the basis of an example from the sports medicine literature, to contrast the effect of recurrent events on confidence intervals generated with unadjusted and adjusted univariate statistical techniques. Second, to demonstrate the implementation of a multivariate regression technique on data containing recurrent data and confounding variables, using data from the exercise sciences. Third, the use of two disparate examples should dispel the notion that the statistical techniques highlighted in this paper have limited application.