Worsening Dual-Task Gait Costs after Concussion and their Association with Subsequent Sport-Related Injury.

Prior studies suggest that concussion may lead to an increased risk of a subsequent time-loss sport-related injury, but the mechanisms responsible are unknown. We measured the symptom and dual-task gait outcomes for athletes initially post-concussion and after clinical recovery. Participants then self-reported any additional injuries incurred in the year after their concussion. Forty-two athletes (52% female, mean age = 16.8 ± 3.2 years) completed the study. They underwent a dual-task gait evaluation and symptom inventory within 21 days post-concussion, and again after they were deemed clinically recovered. Approximately one year later, participants documented if they had sustained any subsequent sport-related injuries. The repeated measures analysis of variance (ANOVA) was used to evaluate changes in dual-task gait and symptoms across time and between groups. A significant group*time interaction (p = 0.02) indicated that the group that went on to sustain a subsequent time-loss injury after returning to sports (n = 15) demonstrated significant average walking speed dual-task cost worsening across time (-17.9 ± 9.1% vs. -25.1 ± 12.5%; p = 0.007). In contrast, the group that did not sustain an additional injury walked with consistent dual-task cost values across time (-25.2 ± 9.2% vs. -24.6 ± 8.4%; p = 0.76). Symptoms improved for all participants (main effect of time, p < 0.001; Post-Concussion Symptom Scale [PCSS] = 25.0 ± 16.9 vs. 2.8 ± 7.5; p < 0.001), but did not differ between groups (p = 0.77). Significant dual-task gait cost worsening throughout concussion recovery was associated with time-loss injuries during sports in the year after a concussion. These findings indicate that worsening ability to execute a concurrent gait and cognitive task may relate to the risk of incurring an injury during sports after clinical concussion recovery.