Abstract
Background: Rugby union is a popular contact sport during which high impact collisions frequently occur. There is concern for the overall brain health of those playing the game, as concussion is a potential outcome of high impact collisions. Repeated sub-concussive collisions may compromise rugby players' neurological integrity, but little is known about the effects on young brains. The brain is still developing during adolescence and may generally be more susceptible to injury, but minimal objective research data are available regarding head acceleration events experienced by junior players.
Results: Forty-one adolescent male rugby players underwent pre- and post-season MRI scans and neuro-cognitive assessments. Participants were fitted with instrumented mouthguards to record head acceleration events experienced during the season. Post-season processing of MRI scans focused on within-subject analysis of pre- to post-season changes in white matter as measured by diffusion tensor imaging. Linear mixed models were used to investigate correlations between neurological changes and cumulative head impact loading recorded by the mouthguards. MRI results indicated a non-significant difference between pre- and post-season for data relating to brain structure and function, including white matter microstructure, in response to one season of contact training and match play for under-16 male rugby players, as measured by diffusion tensor imaging. These results held irrespective of level of exposure.
Conclusions: Our data suggest that exposure to one season of rugby does not appear to result in neurological compromise. The statistical non-significance reported for the main outcome measure also held when controlling for variables, such as training age and headgear use. Although pre- to post-season differences were statistically non-significant, the long-term effects of high exposure may be of clinical significance going forward. Further research, particularly using longitudinal designs, is needed to further elucidate the potential for microstructural neurological changes in adolescent rugby players.