693 MEP165 – Head acceleration exposure during show jumping: measurements of an olympic-level equestrian’s sub-concussive head acceleration events throughout the phases of jumping

AbstractBackground Repetitive head accelerations may negatively affect neurobehavioral health. Equestrian sports are known to convey a high injury risk, but little is known about routine head acceleration exposure (HAE) associated with show jumping.Objective To characterize non-contact HAEs of an Olympic-level athlete and evaluate the associated kinematics (linear acceleration, rotational velocity and acceleration).Design HAE acquired from anOlympic-level rider during seven (7) different practice sessions with obstacles ranging in height from 0.61 m- 1.4 m.Setting An Olympic level athlete in Saugerties, NY, USA.Patients (or Participants) A rider with experience as a US show jumping Olympic team alternate, who is registered/ranked in Fédération Equestre Internationale (FEI). Interventions (or Assessment of Risk Factors) The rider was instrumented with a custom-fitted mouthpiece embedded with a triaxial accelerometer and gyroscope. The device recorded continuously at 200 Hz for 5-minute periods. Two cameras recorded and were time synchronized to the mouthpiece data as the rider navigated show jumping courses. Main Outcome Measurements HAE event processing was performed in phases. Activities were characterized into 4 categories: jump (approach/take-off, flight/bascule, landing) and obstacle refusal by the horse (Table 1). Results Within the phases of jumping, the rider experienced similar kinematics. Refusal was associated with the highest kinematics. See table 2.ConclusionHAEs associated with jumps present the lowest values during practice. These were associated with rider body positioning to achieve proper equitation, implying the preparation minimized HAE magnitudes.Metrics were highest for unanticipated events (refusals), with the rider making fewer adjustments to minimize HAEs.The largest (95 percentile) magnitude events (refusal, 9.84 g's and 10.5 rad/s) compare to the average for a youth football head impact (11.6 g, for linear acceleration) or an average dirt track crash or youth hockey check (9.8 to 10.5 rad/s, for rotational velocity). View this table:View inline View popup Abstract 693 Table 1 Description of each category segmentedView this table:View inline View popup Abstract 693 Table 2 Median and 95th% CI for linear acceleration, rotational velocity and rotational acceleration of rider