The effects of serial assessment using the trail making test in elite rugby league players

The aim of the study was to map trajectories of inter- and intra-individual cognitive performance in non-injured elite rugby players to further understand the effects of serial cognitive assessment in athletes at risk of concussion.

The Trail Making Test (TMT) was administered to male elite rugby league players (N = 38) at three time-points pre-season and on average 6.8 times per month during a playing season. Three players were excluded from the analyses due to concussion or suspected concussion. The data were analyzed using multilevel models including fixed and random effects of time to assess within- and between-individual variability.

Time was the greatest predictor of both TMT-A and TMT-B scores; test performance improved until it reached a plateau and then remained stable. The reduction of within-individual variance indicated that test repetition contributed to improvements in TMT-A and TMT-B performance within each player. Importantly, performance was significantly different between players at first testing and over the course of a playing season which indicated performance heterogeneity within one cohort of elite rugby league players.

The current study has contributed to further understanding pre-injury cognitive performance in elite rugby players and indicated the need for future studies to implement strategies for reducing practice effects. Most importantly, these findings are relevant when assessing cognitive functioning in athletes at risk of concussion. This study emphasized the need to account for variability in performance pre-injury, the assessment of potential performance confounds and recommends the application of methods to reduce practice effects.