The Effect Of Treadmill Exercise On A Visual Attention Dual-task In Athletes With And Without Recent Concussion

Sport-related concussions (SRC) affect neurocognitive functioning (e.g., visual attention, dual-tasking), that may contribute to an elevated injury risk after return to play (Herman et al., 2015). Since athletes perform at higher levels of exertion in sport, it is important to understand how exertion affects visual attention and dual tasking in athletes after SRC. PURPOSE: To investigate how treadmill exercise affects dynamic visual acuity (DVA) and balance in athletes with and without recent SRC while standing. METHODS: Athletes with recent SRC who had returned to play (CONC = 10; age = 21.6, SD = 2.1) were compared to athlete controls (CONTROL = 20; age = 19.9, SD = 1.5). Participants completed a treadmill exercise protocol, which included 2-minute intervals that increased incline by 2% until reaching 85% maximum heart rate. A DVA program presented a Tumbling ‘E’ target in four orientations while in random continuous motion at 30°/s (Yee et al., 2021). When participants selected the orientation of the ‘E’ using a keypad, the target switched orientations and reduced in size with correct responses. The lowest threshold was scored as the log of the minimum angle of resolution (logMAR). The DVA task was viewed standing on a force plate (1000 Hz) at four time points: 1) pre-exercise, 2) immediately, 3) 10-minutes, and 4) 20-minutes post-exercise. DVA performance was calculated as the difference in DVA score from pre- to post-exercise. Balance was analyzed as the root mean square of centre of pressure displacement (dCOP) in anterior-posterior (A-P) and medial-lateral (M-L) directions. RESULTS: Findings revealed no main effects of group or time for DVA performance. However, main effects of time indicated increased A-P (F = 2.93, p < .05) and M-L dCOP (F = 3.05, p < .05) immediately post-exercise in both groups. Increased A-P dCOP for CONTROL persisted 20-minutes post-exercise (p < .05), while greater variability was observed for CONC (95% CI Time 1: CONTROL = 0.27-0.46 cm, CONC = 0.34-0.61 cm; Time 4: CONTROL = 0.49-0.69 cm, CONC = 0.37-0.63 cm). CONCLUSIONS: Visual attention performance was maintained after exertion for athletes despite history of SRC. However, greater variability in balance control after exercise reflects heterogeneity in dual-task performance and may affect some athletes after returning to sport from SRC.