Discriminant and Prognostic Validity of the Multimodal Exertional Test (MET) for Athletes with Concussion

Exertional tests have become an informative tool to assist with clinical concussion management and return-to-sport medical decisions. However, current tests are resource intensive and thus, we developed a widely accessible, multimodal exertional test (MET). The objectives of this study were: (1) To evaluate the discriminant validity of the MET by examining sex-stratified differences in symptoms, heart rate (HR), and performance metrics between concussed and healthy athletes; and (2) To assess the predictive (prognostic) validity of the MET by determining whether week 1 MET performance predicts time to medical clearance. This study was conducted at a single academic institution and affiliated sport medicine clinic in Toronto, Canada, with participants recruited between August 2022 and November 2024. 115 interuniversity athletes (female n=49, male n=66) completed the MET at off-season and 55 interuniversity athletes with concussion (female n=37, male n=18) completed the MET up to six times at 1-, 2-, 3-, 4-, 6-, and 8-weeks post-injury. Average and maximum HR, symptoms, performance metrics, and MET pass/fail status were measured prior to and during the protocol. Probabilistic hierarchical models were implemented to estimate differences between concussion and healthy athletes (discriminant validity) and negative binomial analyses were used to examine whether MET performance predicted time to medical clearance (predictive validity). At 1-week post injury, concussed athletes exhibited greater symptom provocation during the MET compared to healthy athletes, with differences after each task. MET failure rates were highest during weeks 1 (63%) and 2 (49%) and declined through week 8. Athletes who passed the MET at week 1 recovered 20.6 days faster (90% Credible Interval [CrI] = 4.9–36.8 days, posterior probability [pprob] > 0 = 97.7%) than those who failed. The MET demonstrates discriminant validity by eliciting greater symptom provocation in athletes with concussion compared to healthy athletes. Improvements in symptoms and completion rates over 8 weeks indicate recovery-related gains in exertional tolerance. The MET also demonstrates predictive validity, as passing the test at week 1 was associated with faster time to medical clearance, supporting its potential utility as an early prognostic tool in concussion management.