Comparison of physiological outcomes after dynamic exertion between athletes at return to sport from concussion and controls: Preliminary findings.

OBJECTIVES: Compare physiological (heart rate, heart rate variability, and blood pressure), performance (change-of-direction task completion time and errors), and clinical (symptoms and rating of perceived exertion) outcomes during dynamic exertion between athletes at return to sport after concussion to healthy athlete controls. DESIGN: Case control. METHODS: A sample of 23 (Female = 10; 43.5 %) athletes at medical clearance to play/activity from concussion (CONCUSS) and 23 sex-, age-, and sport-matched healthy athletes (CONTROLS) completed a 5-min seated rest before and after the dynamic exertion test. Independent sample t-tests were used to compare CONCUSS and CONTROLS for completion time, heart rate, and blood pressure; and Mann-Whitney U tests for symptoms, perceived exertion, and errors. A series of ANOVAs were conducted to compare heart rate variability between groups across pre- and post-exercise rest periods. RESULTS: There were no differences in heart rate, blood pressure, symptoms, perceived exertion, and errors. CONCUSS were faster on Zig Zag (p = .048) and Pro Agility (p = .018) tasks, reported lower symptom severity (p = .019), and had lower post-EXiT HRV (p < .049) than CONTROLS. CONCLUSIONS: Performance, symptoms, perceived exertion, and blood pressure outcomes from dynamic exertion were equivocal between athletes at medical clearance from concussion and healthy controls, which provide empirical support for dynamic exercise to inform medical clearance clinical decision making for sport-related concussion. However, differences in autonomic nervous system functioning indicate that additional research is needed to examine temporal changes in heart rate variability and other physiological outcomes following dynamic exertion.

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

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.

BACKGROUND: The dynamic exertion test (EXiT) was developed to help inform return to play after sport-related concussion, but some factors may threaten the internal validity of EXiT and affect clinical interpretation. OBJECTIVE: To compare age, sex, BMI, and sport types across EXiT physiological [pre-EXiT and post-EXiT percentage of maximum heart rate (HR %max) and blood pressure (BP)], performance (change-of-direction task completion time and committed errors), and clinical [symptoms and rating of perceived exertion (RPE)] outcomes among healthy adolescents and adults. STUDY DESIGN: Cross-sectional. METHODS: Eighty-seven participants ( F = 55, 37.4%) reported symptoms and RPE during the EXiT, which consists of a 12-minute treadmill running protocol, and the dynamic circuit, ball toss, box shuffle (SHUF) and carioca (CAR), zig zag (ZZ), proagility (PA), and arrow agility (AA) tasks. Independent samples t tests were conducted for pre-EXiT and post-EXiT HR %max and BP and change-of-direction task completion time and Mann-Whitney U tests for errors, symptoms, and RPE. A series of 1-way analysis of variance (ANOVAs) and Kruskal-Wallis H tests were conducted to compare collision, contact, and noncontact sport types. RESULTS: Adolescents had lower completion time across AA ( P = 0.01) and male athletes lower than female athletes on CAR, ZZ, PA, and AA ( P < 0.04). Male athletes reported greater RPE after the SHUF, CAR, and AA ( P < 0.03). HR %max , errors, and symptoms were equivocal across all subgroups ( P > 0.05). CONCLUSION: Age and sex should be considered in the interpretation of performance and clinical, but not physiological, EXiT outcomes. The EXiT is a standardized exercise assessment and generalizable to healthy athletes.

The Dynamic Exertion Test for Sport-Related Concussion: A Comparison of Athletes at Return-to-Play and Healthy Controls.

PURPOSE: To describe the Dynamic Exertion Test (EXiT) by comparing physiological, performance, and clinical outcomes between athletes medically cleared following sport-related concussion (SRC) and healthy controls. METHODS: One hundred four (female = 41, 39.4%) participants (14-21 y of age) including 52 medically cleared for return to play at 21.48 (15.40) days following SRC and 52 healthy athletes completed the EXiT involving (1) 12-minute aerobic component and (2) 18-minute dynamic component including 2 functional movement and 5 change-of-direction (COD) tasks. Physiological (heart rate and blood pressure), clinical (endorsed symptoms and rating of perceived exertion), and performance (COD-task completion time and errors) outcomes were collected throughout EXiT. Participants also completed the Postconcussion Symptom Scale and vestibular/ocular motor screening before EXiT. Independent-samples t tests were used to compare groups on resting heart rate and blood pressure, COD-task completion time, and Mann-Whitney U tests on Postconcussion Symptom Scale, vestibular/ocular motor screening, and EXiT symptoms, rating of perceived exertion, and errors. RESULTS: COD-task completion time and resting systolic blood pressure and heart rate were similar between groups (P > .05). SRC reported greater rating of perceived exertion during the aerobic component (P < .05) and lower total dizziness (P = .003) and total symptoms (P = .021) during EXiT and had lower near point of convergence distance (P < .001) and total symptoms (P = .007) for vestibular/ocular motor screening than healthy athletes. CONCLUSION: Physiological, performance, and clinical EXiT outcomes were equivocal between athletes at medical clearance following SRC and healthy controls. The multidomain EXiT may help to inform safe return-to-play decision making post-SRC.

A Randomized Controlled Trial of Precision Vestibular Rehabilitation in Adolescents following Concussion: Preliminary Findings.

OBJECTIVE: To compare the effectiveness of a 4-week precision vestibular rehabilitation intervention compared with a behavioral management control intervention for adolescents with vestibular symptoms/impairment within 21 days of a concussion. STUDY DESIGN: This study used double-blind, randomized controlled trial design involving adolescent (12-18 years) patients with a diagnosed sport/recreation-related concussion with vestibular symptoms/impairment from a concussion-specialty clinic between October 2018 and February 2020. Eligible participants were randomized in a 1:1 to either a 4-week vestibular intervention group (VESTIB) or a behavioral management control group (CONTROL). CONTROLS (n = 25) were prescribed behavioral management strategies (eg, physical activity, sleep, hydration, nutrition, stress management) and instructed to perform stretching/physical activity (eg, walking, stationary cycle) 30 minutes/day. VESTIB (n = 25) were prescribed precision vestibular rehabilitation exercises and instructed to perform at-home exercises for 30 minutes/day. Primary outcomes were improvement in Vestibular/Ocular Motor Screening vestibular items (ie, horizontal/vertical vestibular-ocular reflex, visual motion sensitivity) at 4 weeks postenrollment. RESULTS: We screened 310 and enrolled a total of 55 (18%) adolescent patients who were randomized to one of the interventions. Fifty of fifty-five (91%) participants completed all aspects of the study protocol. Participants in VESTIB improved significantly across the intervention period in horizontal (mean difference-1.628; 95% CI [-3.20, -0.06]; P = .04) and vertical (mean difference-2.24; 95% CI [-4.01, -0.48]; P = .01) vestibular-ocular reflex, but not visual motion sensitivity (mean difference-2.03; 95% CI [-4.26, 0.19]) of the Vestibular/Ocular Motor Screening score compared with CONTROLS. CONCLUSIONS: Overall, the vestibular intervention group experienced greater clinical improvements in vestibular symptoms/impairment than controls across the 4-week intervention. TRIAL REGISTRATION: ClinicalTrials.gov: NCT03555370.