53 (10A) Effects of lower body negative pressure and head-up tilt cycling on exercise tolerance; an assessment of post-concussion symptoms

Purpose To compare instrumented mouthguard (iMG)-measured head kinematics between elite Australian football players who undergo a head injury assessment (HIA), and are either medically cleared (HIA) or diagnosed with concussion (HIA+).Methods Head kinematic data were collected over four men's and women's seasons, with impacts leading to an HIA verified through video and timekeeper records.Peak linear acceleration (PLA) and peak rotational acceleration (PRA) were compared between HIA and HIA+ cases.Results Five-hundred and nine men and 612 women had an iMG fitted and participated in at least one season.Twenty-nine HIA+ cases (17 men, 12 women) and 86 HIA cases (24 men, 62 women) had kinematic data verified.In men, HIA+ cases had higher median PLA than HIA cases (68 g [interquartile range (IQR): 49-87] vs. 41 g [IQR: 28-71]; p=0.04), with area under the curve (AUC) analysis indicating fair discriminative ability (AUC = 0.69).Similarly, HIA+ cases had higher PRA (6.6 krad/s [IQR: 4.6-9.0]vs. 3.7 krad/s [IQR: 2.3-6.2];p=0.01), with an AUC of 0.73.In women, HIA+ cases had higher median PLA (62 g [IQR: 48-85] vs. 36 g [IQR: 23-55]; p=0.001) and PRA (6.7 krad/s [IQR: 4.1-8.8]vs. 3.0 krad/s [IQR: 1.8-4.7];p=0.001), both with an AUC of 0.78.Conclusion Higher PLA and PRA measurements were observed in athletes diagnosed with concussion compared to those who were cleared following HIA.Ultimately, iMG kinematics may assist in the identification of players at risk of concussion who require medical screening.