Do football helmets reduce acceleration of impact in blunt head injuries?

Several recent studies suggest that acceleration of the head at impact duri ng sporting activities may have a detrimental effect on cognitive function. Reducing acceleration of impact in these sports could reduce neurologic se quelae. Objective: To measure the effectiveness of a regulation football he lmet to reduce acceleration of impact for both low- and moderate-force impa cts. Methods: An experimental paired study design was used. Male volunteers between 16 and 30 years of age headed soccer balls traveling approximately 35 miles per hour bareheaded and with a helmet. An intraoral accelerometer worn inside a plastic mouthpiece measured acceleration of the head. The he lmet also had an accelerometer placed inside the padding. For more forceful impacts, cadaver heads, both with and without helmets, were instrumented w ith intraoral (IO) and intracranial (IC) accelerometers and struck with a p endulum device. Simultaneous IO and IC accelerations were measured and comp ared between helmeted and unhelmeted cadaver heads. The main outcome was me an peak acceleration of the head and/or brain associated with low- and mode rate-force impacts with and without protective headgear. Results: Mean peak Gs, measured by the mouthpiece accelerometer, were significantly reduced w hen the participants heading soccer balls were wearing a helmet (7.7 Gs wit h vs 19.2 Gs without, p = 0.01). Wearing a helmet also significantly lowere d the peak Gs measured intraorally and intracranially in cadavers subjected to moderate-force pendulum impacts: 28.7 Gs with vs 62.6 Gs without, p < 0 .001; and 56.4 Gs with vs 81.6 Gs without, p < 0.001, respectively. Conclus ions: A regulation football helmet substantially reduced the peak Cs associ ated with "heading" a soccer ball traveling at moderately high velocities. A helmet was also effective in reducing the peak acceleration both intraora lly and intracranially for impacts significantly more forceful than heading a soccer ball.