Repeated Impacts Diminish the Impact Performance of Equestrian Helmets.

The study investigates the effect of multiple impacts on the protective performance of equestrian helmets, showing that continuous hits can decrease their efficacy significantly and increase head injury risk.

Objectives of the Research

• The research had two primary goals. The first objective entailed executing impact attenuation testing on multiple equestrian helmet models frequently used by jockeys in the US, as per the ASTM F1163-15 requirements. This standard specifies the performance criteria for helmets meant for equestrian sports.
• The second objective aimed to quantify the acceleration of the headform and the remaining crush after multiple impacts at the same location.

Methodology

• Seven different helmet models were tested for their impact resistance according to the ASTM F1163-15. A second sample of each helmet was tested for resilience against repeated impacts at the crown area totaling four impacts.
• To create a realistic impact scenario, the helmets were crashed against a flat and equestrian hazard anvil.
• The researchers recorded the acceleration of the headform during all impacts and performed computed tomography scans before the impact and after the first and fourth impacts on the helmet’s crown to measure liner thickness.

Results

• One impact exceeded the 300 acceleration limit within four helmets. With repeated hits, acceleration stayed below 300 for the first and second impacts for all helmets, and only one helmet remained below this threshold for all impacts.
• The liner thickness across all helmet models decreased between 5% and 39% after the first impact and between 33% and 70% after the fourth impact.

Conclusion

• The results show that after an impact, the foam liner in helmets compresses, reducing its ability to lessen head acceleration during subsequent impacts to the same area. This signifies that the helmets lose their effectiveness after repeated hits.
• Therefore, the study recommends that all riders should put on a certified helmet and replace it if they ever suffer a head impact. Helmet replacement after an impact may help decrease a rider’s potential injury risk to their head.