Impact attenuation properties of new and used lacrosse helmets

The National Operating Committee on Standards for Athletic Equipment (NOCSAE) has developed impact attenuation thresholds that protective helmets worn in sport must meet to be commercially available in an attempt to prevent injury. It remains unknown how normal helmet use in athletic activity alters the force attenuation ability of lacrosse helmets. We tested 3 new and 3 randomly selected used helmets from 2 popular lacrosse models (Cascade Pro7, Cascade CPXR). All used helmets had been worn for 3 collegiate seasons prior to testing and had never been refurbished. Helmets were drop-tested using 3 prescribed impact velocities at 6 locations according to the NOCSAE lacrosse helmet standard, and we compared the Gadd Severity Index (GSI) scores between new and used helmets using a repeated measure ANOVA with location as the repeated variable and data separated by impact velocity. All 12 helmets passed the NOCSAE GSI threshold for all testing conditions; however 1 used helmet shell cracked resulting in a failed test. We found a significant main effect for helmet age at the low (F5,50=2.98, P=.02), medium (F5,50=3.71, P=.006), and high (F5,50=2.70, P=.03) velocities. We suspect that helmet use can degrade materials under some conditions, but improve performance in others due to changes in helmet composition from use. The clinical implications of the differences in GSI scores noted remain unclear. Because one helmet shell cracked resulting in a failed test, used helmets should be regularly inspected for cracks or other signs of mechanical fatigue that may weaken helmet integrity.