Test-Retest, Interrater Reliability, and Minimal Detectable Change of the Dynamic Exertion Test (EXiT) for Concussion

Abstract

Background: The Dynamic Exertion Test (EXiT) was developed to inform return-to-play (RTP) decision-making following clinical recovery from sport-related concussion (SRC). The purpose of the current study was to document intrarater and test-retest reliability and minimal detectable change (MDC) scores for physiological [heart rate (HR) and blood pressure], performance (change-of-direction task completion time and errors), and clinical outcomes (endorsed symptoms, perceived exertion) of EXiT, and interrater reliability of performance outcomes. Hypothesis: Healthy athletes would exhibit stable physiological responses to the EXiT across visits, demonstrate consistent change-of-direction task completion time between consecutive trials at each visit, and the fastest time (of 2 trials) across visits, and endorse equivocal symptoms and effort across visits. Study Design: Cross-sectional, test-retest. Level of Evidence: Level 3. Methods: Seventy-nine (female: 34 [43%], 19.6 ± 5.0 years) athletes completed the EXiT at 2 study visits (8.7 ± 4.7 days between visits). Two-way, mixed, intraclass correlation coefficients (ICCs) were used to evaluate intrarater and test-retest reliability. Cronbach’s alpha was used to document the internal consistency of symptoms at each visit, and MDC scores were calculated on the physiological, performance, and clinical outcomes. Results: Measured and percentage of age-estimated maximum HR were reliable following EXiT (ICC = 0.579-0.618). Change-of-direction task completion time (MDC range = 0.75-8.70 s) had good-to-excellent test-retest (ICC = 0.703-0.948) and interrater (ICC = 0.932-0.965) reliability. Symptoms had a high internal consistency at visits 1 ( α = 0.894) and 2 ( α = 0.805) and were reliable across visits (ICC = 0.588). Conclusion: The current investigation established test-retest reliability in addition to MDC scores of an objective dynamic exercise assessment among healthy adolescent and adult athletes. The EXiT may be an objective approach to inform RTP decision-making following SRC recovery. Clinical Relevance: The EXiT is a clinically feasible exertion-based assessment that can be readily administered in a variety of outpatient clinical settings.

The Role of Age, Sex, Body Mass Index, and Sport Type on the Dynamic Exertion Test in Healthy Athletes: A Cross-Sectional Study

“…These findings support the integration of evidence-based exertion prescription recommendations into clinical research. 5,9,43–45…”

“…The test-retest reliability of these outcomes is reported elsewhere. 9 Demographics, Anthropometrics, and Physiological Monitoring Previous diagnosis of concussions, headache/migraine history, learning disability, and primary sport (categorized as noncontact, contact, or collision sport types 27 ) were obtained with a standardized questionnaire. Bodyweight (in kg) was measured using a digital scale (Health-o-Meter) and height (in cm) with a wall-mounted stadiometer (Seca).…”

“…[1][2][3][4] Because the widespread recommendation for the staged progression to RTP, 3 the determination of physical readiness to resume unrestricted sport participation is standardized but with minimal objectivity. 5,6 To address this shortcoming in clinical research, several standardized exertion assessments to inform RTP decision-making have been developed. 4,5,7,8 More recently, the dynamic exertion test (EXiT) was created as a clinically intuitive evaluation to inform RTP decision-making 5,9 and can be interpreted through physiological [age-estimated percentage of maximum heart rate (HR %max ) and blood pressure (BP)], performance (change-of-direction task completion time and errors), and clinical [endorsed symptoms and rating of perceived exertion (RPE)] outcomes.…”

“…5,6 To address this shortcoming in clinical research, several standardized exertion assessments to inform RTP decision-making have been developed. 4,5,7,8 More recently, the dynamic exertion test (EXiT) was created as a clinically intuitive evaluation to inform RTP decision-making 5,9 and can be interpreted through physiological [age-estimated percentage of maximum heart rate (HR %max ) and blood pressure (BP)], performance (change-of-direction task completion time and errors), and clinical [endorsed symptoms and rating of perceived exertion (RPE)] outcomes. A preliminary report examining the EXiT among healthy adolescent and adults found moderate test-retest reliability 9 and established minimal detectable change (MDC) cutoffs for HR %max, systolic and diastolic BP, symptoms, and change-of-direction task completion time.…”

“…4,5,7,8 More recently, the dynamic exertion test (EXiT) was created as a clinically intuitive evaluation to inform RTP decision-making 5,9 and can be interpreted through physiological [age-estimated percentage of maximum heart rate (HR %max ) and blood pressure (BP)], performance (change-of-direction task completion time and errors), and clinical [endorsed symptoms and rating of perceived exertion (RPE)] outcomes. A preliminary report examining the EXiT among healthy adolescent and adults found moderate test-retest reliability 9 and established minimal detectable change (MDC) cutoffs for HR %max, systolic and diastolic BP, symptoms, and change-of-direction task completion time. 5 Although these findings are fundamental to the interpretation of physiological, performance, and clinical EXiT outcomes, the potential confounding effects of factors that may threaten the internal validity have not been investigated.…”