A Comparative Analysis for the Measurement of Head Accelerations in Ice Hockey Helmets using Non-Accelerometer Based Systems

Head impact research involving accelerometer based sensors in sports helmets has been well documented over the past decade; however, the maximum number of players involved in the largest continuous study was 314 over 3 years. Practical methods for using accelerometer arrays present significant power management issues and a requirement for high resolution data during direct head impact injury. The objective of this study was to investigate a reliable and affordable method for measuring direct head impacts for large scale populations by using electromechanically activated force switches instead of accelerometers. An embedded micro-processor and software algorithm captured and calculated voltage activation of the force switches between 80-100 KHz. Laboratory studies conducted on a monorail drop tower using an ISO headform demonstrated the ability to correlate headform acceleration to algorithm reported acceleration. Impacts were performed on hockey helmets at 2.0, 2.5 and 3.0m/s for an aggregate percent difference of 8.9% at the front, front boss, side, rear boss and rear impact locations, respectively. The use of force switches in sensors affixed to sports helmets is viable at exceptionally low cost monitoring and analyzing reliable direct head impact linear acceleration.