Conventional helmets are lined with different types of absorbency materials, such as foam or fluid-filled pads, intended to conform to the shape of the head and dissipate energy. Upon impact, the pads deform. However, the material lacks resiliency and thus degrades over time. Gel- and air-filled pads have to be refilled and monitored for leaks. What’s more, these materials can’t adjust to the amount of force.
A cable runs around the flexible cap from the back of the helmet toward the front, and through the helmet’s chin straps. When a player pulls on the chin straps, the chin piece pulls the cable downward. This secures the back and sides of the helmet around a person’s head, so the inside of the helmet is literally adapting to the person’s head size and shape, says Ferrara.
The Xenith helmet is one more step in a football-helmet design that seems to be effective in absorbing energy and dispersing the impact so that it’s not all going to the head, says Laurence Young, a professor of aeronautics and astronautics at MIT. Young is also working on a helmet design, still in the research phases, based on a similar concept.
The Xenith helmet will be available in one size this spring, and a full range of sizes will be released in 2009. Ferrara also plans to use the helmet technology in other sports helmets, as well as in military helmets.