Physiological evaluation of the Calgary adapted aRm ergometer (CARE) concussion exertion test in adolescent athletes:...

Exertion testing helps inform exercise prescription during concussion recovery. The Calgary Adapted aRm Ergometer (CARE) test, developed as the first upper-body specific exertion test, aims to improve accessibility and inclusivity in concussion care. While initial development was conducted in adults, its applicability in adolescents remains unknown. This study compared physiological responses between the CARE test and the Calgary Concussion Cycle Test (CCCT) in non-disabled adolescent male and female athletes. Fifteen females and fifteen males (aged 14-17) performed CARE and CCCT to volitional fatigue. Response differences, Bland-Altman plots, effect sizes, intraclass correlation and moderation by sex for heart rate (HR), middle cerebral artery velocity (MCAv), volume of oxygen consumption ( ${\dot{V}}_{O_2}$ ), minute ventilation ( ${\dot{V}}_E$ ) and end-tidal carbon dioxide ( $P_{\mathrm{ETC}{O}_2}$ ) were analysed at 25%, 50%, 75% and 100% of peak exertion levels. CARE elicited lower absolute values for HR, MCAv, $P_{\mathrm{ETC}{O}_2}$ , ${\dot{V}}_{O_2}$ and ${\dot{V}}_E$ compared to CCCT, with differences and 95% limits-of-agreement becoming more pronounced at higher intensities. For mild-to-moderate exercise (25-50% exertion), the range typically used in clinical concussion testing, HR and MCAv differences were small for both sexes. Near maximal intensity, the HR gap widened, but MCAv was comparable. Sex did not modify the relationship between tests for HR and MCAv. While CARE predominantly employs smaller muscle mass than CCCT, results showed robust and relatively comparable physiological responses between tests and between male and female adolescents. These findings further support CARE as an accessible and inclusive post-concussion exertion test for those not able to perform lower-body protocols.