Study Analyzes Skull Protection by Bicycle Helmets
Bicycle accidents are a common cause of traumatic injury in the United States. The most recent statistics indicate that there were an estimated 500,000 bicycle-related injuries treated in U.S. hospital emergency rooms in 2004. Of those, 69,500 were head injuries, and of the 600 bicycle-related deaths, about two thirds were attributed to traumatic brain injury (TBI).
Researchers recently assessed the level of protection provided by children’s bike helmets. The results of this study, Quantification of the Protection Granted by Children’s Bicycle Helmets Using Engineering Tools and Experimental Design, will be presented by Chris A. Sloffer, the co-author of this study is Julian J. Lin, MD.
Four human skulls were utilized for this study. Skulls were soaked in water and filled to weigh four pounds to correspond to the approximate weight of a child’s skull. An accelerometer was mounted to each skull to facilitate measurement of the forces sustained by the skulls during testing. Identical, commercially available bicycle helmets were obtained for use in each step of testing.
Current industry testing standards require helmets to be placed on a head form and dropped from various heights onto a metal anvil. The helmets pass if they do not sustain injury. In this study, each helmeted skull was dropped from progressively greater heights of two to four feet. Impact decelerations experienced by the skulls were recorded. Skulls without helmets were dropped beginning at two feet and increased until failure (fracture). Decelerations experienced by these skulls were also recorded. As an additional method of testing, compressive force was applied to skulls, both with and without helmets, as well as to helmets without skulls inside. Forces tolerated were recorded in each of these categories, and digital video records were taken of all testing. Children’s bicycle helmets provide measurable protection in terms of both reducing the deceleration experienced by the child’s head and protecting against direct compressive force.