The Effect of an Exertion Protocol on Cognitive and Functional Performance in Adolescents After Concussion

BACKGROUND: Over the last decade, prevalence of reported concussions has increased 60%, particularly in the adolescent population. Premature return-to-play is associated with prolonged recovery, worsening symptoms, and higher rates of subsequent musculoskeletal injury. Better understanding of the effects of physical exertion after concussion is needed to ensure safer return-to-play. HYPOTHESIS: Cognitive performance would decline, and biomechanical deficits would become more apparent with increasing task difficulty in an exerted state. STUDY DESIGN: Cross-sectional. LEVEL OF EVIDENCE: Level 3. METHODS: Adolescents diagnosed with concussion completed testing when cleared to begin return-to-play progression, which included simple (SG), dual-task (DT), and multi-task (MT) gait, completed before and after an exertion protocol. For SG, participants walked 10 meters. Dual-task required walking while reciting 3-digit numbers in reverse order, and MT involved typing a recited statement into a smart device while walking. Temporal parameters were calculated, and performance was recorded for DT and MT. Wilcoxon signed-rank tests were performed to compare variables of interest pre- and post-exertion (α = 0.05). RESULTS: Thirty patients (20 female, age 14.4 ± 1.9 years) were tested within 2 weeks after clearance to begin return-to-play progression. Participants demonstrated decreased cadence and walking speed with SG post-exertion, whereas these increased during DT and MT. Multi-task performance improved from 77% pre-exertion to 90% post-exertion (P = 0.034), whereas DT performance did not significantly improve (P = 0.298). Variability of temporal parameters decreased for SG, whereas no differences in variability were observed for DT and MT. CONCLUSIONS: Significant cognitive and functional performance changes were observed after an exertion protocol in adolescent athletes recently cleared to begin the return-to-play progression. Predominantly, MT elicited improved performance and faster walking speed, with longer strides compared with pre-exertion. Minimal differences were observed in variability comparing pre-exertion with post-exertion gait tasks. CLINICAL RELEVANCE: Post-exertion testing may provide additional information in the determination of concussion recovery and return-to-play beyond what is measured clinically.