Dynamic Balance Deficits Following Concussion

Abstract

Dynamic balance deficits during gait have been observed following concussion and often linger beyond an athlete’s return to activity. However, there are limited data describing balance performance during functional movements. PURPOSE: To determine if participants with a concussion history demonstrate dynamic balance deficits compared to control participants during single leg squats and single leg hops. METHODS: Participants with a concussion history (n=15, median time since concussion=126 days; range 28-432) were matched by age, mass, and height to control participants (n=15). Participants performed single leg squats while standing on a force plate from which center of pressure path and speed were obtained. During single leg hops, participants jumped off a 30cm box placed 50% of their height behind a force plate, landed on a single leg, and attempted to come to a stable position as quickly as possible. Single leg squat outcomes were averaged across legs as there were no between leg differences (p=0.480; dominant leg=leg participant kicks ball with). Time to stabilization (TTS; time taken for center of pressure to stabilize after landing) was calculated for the single leg hop, and each leg was analyzed separately due to concerns with between leg differences (p=0.055). Groups were compared using ANCOVA, controlling for average days since concussion. RESULTS: No group differences were observed for single leg squat center of pressure path (p=0.197) or speed (p=0.765). Dominant leg TTS was not different between groups (p=0.431). The previously concussed group demonstrated longer TTS than the control group during non-dominant leg single leg hop (p=0.024; mean diff.=0.34 s; 95%CI: 0.04,0.64). CONCLUSIONS: Lingering dynamic balance control deficits after concussion may contribute to an increased risk of musculoskeletal injury. While single leg squat may not challenge balance control sufficiently, future study of the more dynamic single leg hop is needed to determine the potential diagnostic and prognostic value following concussion. Non-dominant limb static balance assessment is common following concussion. Slight balance impairments may be better identified when assessing the non-dominant leg due to preexisting between limb neuromuscular control disparities, as was the case in our investigation.