46 (5A) Exploring the incidence, magnitude and causes of head acceleration events measured by instrumented mouthguards in elite men’s and women’s Australian football

Purpose To examine the effect of calorically matched light (Rating of Perceived Exertion [RPE]-9) and moderate (RPE-13) daily exercise on Blood Lactate (La -) and days until symptom resolution (SRA) in collegiate athletes with concussion.Methods Participants (n=10,40% female) were randomly assigned to initiate a treadmill walking protocol at an RPE-13 (n=6, 33.3% female) or RPE-9 (n=4, 50% female) within 72 hours of concussion.Initial symptom severity was assessed with the Revised Head Injury Scale at Visit 1. Blood La - (mmol) was measured before and after exercise at Visit 1 and Visit 2(SRA).Initial symptom severity and days to SRA were compared using independent t-tests.An ANCOVA compared change in La -between Groups at Visits 1 and 2, controlling for initial total symptom severity.Analyses were performed with a= 0.05.Results Although underpowered, initial symptom severity was greater in RPE-13 (32.013.1)compared with RPE-9 (16.8 8.62).Average heart rate was similar between RPE-13 (116 14.0 bpm) and RPE-9 (1039.97bpm) groups at Visit 1. RPE-13 (1318.08bpm) was significantly higher than RPE-9 (10913.0 bpm [p=0.01]) at Visit 2. Days until SRA were similar between RPE-13 (9.04.29) and RPE-9 (6.254.99)groups (p>0.05).Though not significant, change in La - between RPE-13 (1.282.06;0.021.33)and RPE-9 (-2.20 2.89; 0.570.51)at Visits 1 and 2 showed differing patterns.Conclusions Though our study was underpowered to evaluate how exercise intensity influences La -responses in collegiate athletes with concussion, both RPE-13 and RPE-9 groups achieved SRA approximately three and four days sooner than collegiate athletes, with similar symptom severity, who received standard-of-care concussion management.