Impact performance of modern football helmets.

Linear impact tests were conducted on 17 modern football helmets. The helmets were placed on the Hybrid III head with the neck attached to a sliding table. The head was instrumented with an array of 3-2-2-2 accelerometers to determine translational acceleration, rotational acceleration, and HIC. Twenty-three (23) different impacts were conducted on four identical helmets of each model at eight sites on the shell and facemask, four speeds (5.5, 7.4, 9.3, and 11.2 m/s) and two temperatures (22.2 and 37.8 °C). There were 1,850 tests in total; 276 established the 1990 s helmet performance (baseline) and 1,564 were on the 17 different helmet models. Differences from the 1990 s baseline were evaluated using the Student t test (p < 0.05 as significant). Four of the helmets had significantly lower HICs and head accelerations than the 1990 s baseline with average reductions of 14.6-21.9% in HIC, 7.3-14.0% in translational acceleration, and 8.4-15.9% in rotational acceleration. Four other helmets showed some improvements. Eight were not statistically different from the 1990 s baseline and one had significantly poorer performance. Of the 17 helmet models, four provided a significant reduction in head responses compared to 1990 s helmets.