Annals of Biomedical Engineering
January 25, 2025
Purpose
To evaluate the population variation in head-to-helmet contact forces in helmet users.
Methods
Four different size Kevlar composite helmets were instrumented with contact pressure sensors and chinstrap tension meters. A total number of 89 volunteers (25 female and 64 male volunteers) participated in the study. The length, width, and circumference of their heads were measured and each volunteer was assigned a helmet size. Volunteers were asked to wear the helmet in three different configurations and the chinstrap tension and contact force between the head and each of the seven interior pads were recorded.
Results
The majority of forces measured on any individual pad were between 0 and 5 N. However, some users exhibited pressure points with forces as high as 30 N. The contact force distribution is non-uniform across the interior of the helmet, with the largest force concentrated at the front. Head shape is a major driver of the observed contact force. There was a statistically significant difference between female and male volunteers, and between groups with different experience levels.
Conclusions
The fit of helmet systems is highly subject specific. The current metrics used to assign helmet sizes may not accurately predict correct helmet fit.
References
Cobb, B. R., et al. Quantitative comparison of Hybrid III and national operating committee on standards for athletic equipment headform shape characteristics and implications on football helmet fit. Proceedings of the Institution of Mechanical Engineers, Part P: Journal of Sports Engineering and Technology. 229:39–46, 2015.