Convergent Validity Of A Brief Dynamic Exertion Test (B-EXiT) For Concussion And The Buffalo Concussion Treadmill Test Among Healthy Controls

Graded aerobic exercise testing is currently used to evaluate exercise intolerance post-concussion. However, this testing has been limited to stationary cycling or treadmill running, which requires access to expensive equipment that may be unavailable to many clinicians. There is a need for a widely accessible, clinically feasible, post-concussion exertion assessment that can illicit comparable physiological responses to current assessments. PURPOSE: Compare physiological responses (heart rate [HR], blood pressure [BP]) and symptoms using a new, brief version of the Dynamic Exertion Test (B-EXiT) protocol to the Buffalo Concussion Treadmill Test (BCTT) in healthy adults. METHODS: Twenty-five (F = 14, 56%; 23.3 ± 3.6 years) healthy, physically active (per ACSM criteria) adults completed the BCTT and B-EXiT at one study visit in randomly assigned order, as well as pre- and post- exercise resting HR, BP, and self-reported symptoms on the Post-concussion Symptom Scale (PCSS). B-EXiT consists of 5 equidistant cones in a 5X5 meter space, during which participants touch cones in response to images presented on an iPad in synchronization with a metronome. Both protocols progressively increase intensity, with Rating of Perceived Effort (RPE) and HR recorded each minute until volitional exhaustion. Paired samples t-tests and effect sizes (Cohen’s d) were conducted to compare maximal HR, exercise duration, RPE, resting HR and BP, and PCSS total symptoms. RESULTS: Maximal HR was similar between B-EXiT (189.9 ± 5.8 bpm) and BCTT (189.8 ± 6.0 bpm). Compared to the BCTT, the B-EXiT involved longer exercise duration (21.9 ± 1.6 vs 20.5 ± 1.7 min; p = 0.001, d = 0.756) and lower RPE (16.7 ± 2.7 vs 18.4 ± 1.4, p = 0.003, d = 0.649). There were no differences between B-EXiT and BCTT conditions across pre- and post-exercise resting HR and BP, and PCSS and symptoms (p > 0.05). CONCLUSION: Maximal HR, post-exercise physiological responses, and concussion symptoms during the B-EXiT and BCTT were comparable. However, small differences in RPE, symptoms, and exercise duration should be considered when interpreting B-EXiT performance. Overall, the findings provide preliminary evidence for B-EXiT as a low-cost, but comparable alternative to the BCTT, which can help inform clinical return to sport decisions following concussion. This research was supported by the Dr. Freddie Fu Doctoral Student Grant from the University of Pittsburgh, and by the Clinical Sports Medicine Endowment from the American College of Sports Medicine Foundation