Bicycle helmet retention system testing and evaluation

Bicycle Helmet Size, Adjustment, and Stability

“…A larger amount of slack prescribed in the adjustment for stability testing in the standard would better approximate the adjustment on wearers and give a more conservative measure of stability. This is in line with recommendations by Mihora et al (2007).…”

“…They found that helmets were worn loosely with an average 4.7 cm of slack. Dynamic stability testing in the study (Mihora et al 2007) using a pendulum device found that with this amount of chin strap slack, a bicycle helmet to ground impact resulted in significant forward rotation of the helmet on the headform and the helmet could easily be rotated off the head after the test. These papers suggest that the position of the helmet on the head (e.g., tilted back), the congruity in shape and size between the helmet and head shape (i.e., fit), and the adjustment of the restraint system are important factors in determining helmet stability and crash performance.…”

“…Rivara et al (1999) identified helmet wearing position and fit as factors that contributed to head injury risk in hospitalized child cyclists: cyclists who wore their helmets tilted posteriorly had a 52% greater risk of head injury than those who had it positioned at the correct position, and head-injured cyclists wore helmets that were significantly wider than their heads compared to uninjured cyclists. Mihora et al (2007) measured the distance between the bottom of the helmet retention strap and the chin of 36 cyclists when a 0.5 kg load was applied. They found that helmets were worn loosely with an average 4.7 cm of slack.…”

Finite element modelling of equestrian helmet impacts exposes the need to address rotational kinematics in future helmet designs

“…There have been many technical studies regarding bicycle helmets (Mills 1990; Andersson et al 1993;Mills and Gilchrist 2003;Depreitere et al 2004;Van Lierde et al 2005;Mills and Gilchrist 2006a,b;Mihora et al 2007). These studies focus only on linear acceleration reduction and on the performance of the foam liner, in terms of energy absorption by measurement of force-displacement.…”