THE FOOTBALL HELMET, PART 2
By Dr. Ken
Last month’s discussion indicated that the design and construction of any football helmet involves a number of well considered compromises. In one of the early installments of HELMET NEWS I quoted the statement made by Dr. David Halstead that the safest football helmet would be a padded, metal deep-sea diving helmet. He also noted that you couldn’t wear it on the field, the lack of ventilation and heat dissipation was dangerous, the materials would no doubt kill or maim any other player upon contact, it would be too heavy to actually wear, and a host of other comments to indicate the ridiculousness of this proposal. The point however, was well made and one not often considered by the lay person who is interested in helmet design. The “blend” of correct materials for both the shell and padding layers of the helmet, the actual shape of the helmet, the “fit”, and numerous other factors distinguish the football helmet from those used in other activities. For those who were teenagers or young adults in the mid to late 1960s, EASY RIDER is a movie that is easily recalled. One scene that remains fresh in my mind, and that of a number of friends of approximately my age, is that of Jack Nicholson seated on the back of a motorcycle wearing his high school football helmet as he sets off with the movie’s two protagonists to a new life. I have never been a motorcycle enthusiast but I assume that wearing a football helmet would be more effective in preventing injury if one “dumped” their bike relative to wearing no helmet. However, I would also assume that wearing a properly designed motorcycle helmet, would be a lot more effective in preventing injury than wearing any other type of helmet, including a football helmet. The design, materials, and construction have to consider and meet the specific needs of the activity.
Resistance to penetration and abrasion, ability to deflect a blow and the type of impact blow the helmet is exposed to, overall size and weight, ability to provide heat dissipation, ventilation and air flow, and the way in which it affects hearing and vision while being worn for its primary application are all considerations. For those designing and building football helmets, the most important factor is the helmet’s ability to handle a rapidly applied force. I learned more about this when visiting the Southern Impact Research Center where helmets of all types are tested and examined. The testing equipment is fascinating and while the work itself is repetitive, it is highly interesting and absorbing. I watched tennis balls being shot at various points on protective goggles (which are also tested there), lacrosse balls shot at lacrosse helmets and facemasks, head molds wearing various helmet designs being exposed to vertical and horizontal forces. In short, it was for me, a unique and highly informative experience. The artificial head forms with their instrumentation, allows the examiner to measure impact without exposing a person to these damaging blows. The impacts closely replicate the types of blows that a football player, wearing the specific helmet, would encounter on the field and more! Impact surface features, ambient temperature, angle of impact delivery, and other factors are all considered when testing. Helmets are struck by other helmets, pads, unpadded body parts, and both artificial and natural grass surfaces. All of these factors are taken into account and then compared to established standards to insure that the helmet will in fact, deflect, absorb, or dissipate a certain level of impact force. These forces differ, for example, from a hockey helmet that will most often strike a cold and hard surface and do so in a cold environment. Helmets worn by combat participants must protect against metal fragments moving at a high rate of speed. Motorcycle helmets must be designed to protect against one major impact while the football and hockey helmets must protect against repetitive blows. When the head forms are exposed to these impacts, the kinetic energy approximates that which will be encountered on the field. Direction of impact is also considered and obviously, with a football helmet, that impact can come from any direction which will affect both testing standards and the ultimate shape of the helmet.
More on this next month!