Experimental biomechanical study of head injuries in lateral falls with skateboard helmet.

Traumatic brain injuries (TBI) are common in sports accidents. Helmets are generally known to provide protection to the head. However, the effectiveness of helmets in mitigating a TBI may be compromised due to the impact location and impact speed. Although it is known that the helmet decreases the linear head accelerations and the resulting head injury potential, to the best of our knowledge, limited research effort has been devoted to the study of the biomechanics of TBI in side impact conditions. The present work is designed to delineate the biomechanics of TBI in a fall impacting the parietal/temporal regions. A standing Hybrid III male dummy with pedestrian pelvis was used. The dummy was placed on a swinging platform for the fall simulation. The drop was achieved by stopping the platform with a block. The platform was swung from a predetermined height and stopped to allow the free fall of the dummy. The test was conducted with and without a skate board helmet. The impact on the dummy’s head was in the parietal and temporal regions. The head impact speed with the floor was approximately 24 kph (6.7 m/sec) The dummy was instrumented with tri-axial linear and tri-axial angular head accelerometers to measure the biomechanical injury responses. Results from three tests were compared. The linear head CG acceleration, Head Injury Criteria (HIC) and angular head accelerations were compared. Results suggest that the helmet reduced the linear head acceleration, HIC and angular head acceleration compared to the impact without a helmet. Although the linear head accelerations and HIC were reduced, the angular head accelerations even with the helmet were above nearly all proposed rotational head injury threshold in the literature. The higher angular head accelerations indicate a higher probability of concussion, acute subdural hematoma and diffuse axonal injuries. The present study is an additional step to better understand the biomechanics of TBI and the role of protective headgear systems in sports and recreational accidents.