A biomechanical study of bicycle helmets' effectiveness in childhood.

The authors present the results of a series of impact tests on pedal cycle helmets. 10 helmets were tested using a drop test under three different test conditions: Left frontal/temporal from 1 m, right frontal/temporal from 1.5 m and left occipital from 1 m. Impact force and the acceleration of the headform's centre of gravity in three axes were measured. As a result of the authors' field research on pedal cycle helmets in Australia the 1.5 m drop height was considered to be more representative of a "real" accident than the less severe 1 m height fall. The range of resultant maximal accelerations, 1 m drop height, was 81 g to 193 g; 1.5 m drop height 122 g to 209 g. In comparison a fall without helmet from 0.5 m produced a maximal resultant acceleration of 282 g. Head injury criteria values were for 1 m drops between 201 and 630; from 1.5 m 547 to 1078; and without helmet from 0.5 m 906. The individual helmets are compared on these figures and their merits discussed.