Reply to Fanton et al.: Comment on “Frequency and Magnitude of Game-Related Head Impacts in Male Contact Sports Athletes: A Systematic Review and Meta-analysis”

Abstract

The authors thank colleagues Fanton et al. [1] for their interest in our review recently published in Sports Medicine [2]. We agree with the stated methodological limitations in the current application of accelerometer devices to quantify head impact frequency and magnitude as outlined by Fanton et al. [1] As outlined in the review [2], these issues resulted in the meta-analysis of impact magnitude being limited to American Football only. Having trialled the use of a nonhelmeted accelerometer device in amateur Australian Football [3] and more recently at the elite level (Reyes et al., currently under review) the authors are indeed cognisant of these constraints. Laboratory investigations [4] have also identified that devices such as the X-patch record spurious events, yet also miss head impact events, and that proprietary filters such as the “clack” are not sufficiently reliable. One of the key points highlighted by our attempt to undertake such a review is that in addition to the variability in actual devices across helmeted and non-helmeted sporting codes, variation in sensor impact detection performance (without concomitant video review); determination of peak linear acceleration (PLA)/peak rotational acceleration (PRA) reporting threshold; and reporting standards across training and games versus games only have significantly constrained comparison of the frequency and magnitude of head impacts across sporting codes to date. We recommend that in terms of reporting standards future studies (1) include video verification of head acceleration events; (2) report practice/training and games/matches separately, and; (3) report concussive impacts separately to non-concussive impacts as these factors may inflate means of reported PLA and PRA. Moving forward, medians with 25th and 75th percentiles should be reported as accelerometer data are non-normally distributed. There does, however, appear to be yet quite some way to go before rigorous comparisons can be made across sporting codes.