"Head Injuries"

by Dr. Ken
The change in football rules at all levels, and especially the mandated provisos regarding contact in the high school and collegiate games, has led to a marked reduction in both head related, and cervical spine injuries. Reading the first five installments of Helmet News, Safety First articles may have left the reader with the impression that the modern football helmet does an excellent job of protecting the head. It does but the number of head injuries, with what we term concussion as the primary one, are still frequent enough to be considered a serious problem. Troy Aikman, Steve Young, and others, especially those at the quarterback position, have been especially vulnerable and made concussion injury a "must issue" among NFL owners, players, and medical staffs. 
Let's have a quick summary:
-internal head injuries were the primary cause of on-the-field death prior to 1960.
-with the introduction of the "modern" hard plastic helmet and metal facemask, coaching philosophies and teaching techniques changed so that headfirst hitting became the desired manner in which to make initial contact upon blocking or tackling.
-by the mid-1970s, the primary cause of catastrophic on-the-field injury had shifted from head, to cervical spine (neck) injury.
-In 1976, due in large part to the efforts of Dr. Joseph Torg of Philadelphia, the high school and collegiate rules were changed in order to outlaw or at least reduce, headfirst contact on all plays.
-the three primary mechanisms of injury were noted as: Direct Impact between two moving bodies or Direct Impact between a moving body and a stationary body where axial loading produced a destruction of spinal elements; Deceleration Injury where the cervical spine was crushed between the head and the still moving torso; Rotational Acceleration where the head was "torqued" upon contact, leading to head injury, cervical spine injury, or both.
The above statements still hold true and although injuries to the head and cervical spine have been reduced significantly, there are still injuries with one fatality for every 1.5 million participants per year. The change in the rules and the continued improvement in the helmet itself, have proven to be a positive series of steps. I do not have a background in plastics, but when those of us interested in helmet history think "plastic," I believe we visualize John T. Riddell and his staff making the first plastic helmet with materials that are like the ones we are familiar with today. This of course, was not the case. The first "plastic helmet" was plastic, but it might be more accurate to envision a resin impregnated fabric type material. Remember too that the "first plastic football helmet" is credited as being developed in 1939, at the cusp of the War effort. With a shortage of plastics and materials needed to manufacture plastics, the first plastic helmets I'm sure, were nothing that any of us could imagine, or compare to today's materials. 
Helmet manufacturing has always been a series of compromises. Plastic was, and remains, lightweight relative to its size and our discussion of head and cervical spine injuries indicated that "the less weight, the better." A lighter football helmet will not fatigue the muscles of the neck and upper back area as quickly as a heavier one. The more fatigued the muscles become, the greater the probability of losing a proper head position when applying contact. A lighter helmet provides less mass or weight and we will recall our equation for creating rotational acceleration forces that can be so damaging to both the brain structures and the cervical spine. The heavier helmet has more mass and thus, more potential damage can result from rotational acceleration. The helmet materials and construction must be strong so that it can stand up to repeated blows, repetitive and accumulative damage. This differs from the needs of a motorcycle or bicycle helmet which are constructed with the intent of preventing a single, major damaging blow. The helmet must be constructed so that the wearer can in fact, play the game of football. In the office of the top researcher in the helmet safety field, I was shown a huge, metal diving bell. There was no doubt, that packed with protective foam, I was viewing "the safest helmet possible" for the wearer. Of course, one could never play football in it, could never even realistically walk out of the locker room while wearing it and don't even think about the damage inflicted by trying to play in such a contraption, especially one made of metal. This however, is part of the compromise of helmet construction; light enough not to tire the involved muscles during play, strong enough to stand up to repetitive blows, maintains its shape and function after contact, can be maintained and reused for a reasonable period of time, fits comfortably and in a manner that allows adequate vision, fits so that the safety features of the helmet are in fact available to the user, is ventilated well enough so that heat related illness does not become a factor (think again about the diving bell type of helmet!), and is affordable to both manufacture in quantity and then be purchased by the consumer. Thus, in order to produce a helmet that meets safety requirements, an awful lot of thought and work has been done and continues to be done.
While the safety considerations remain paramount, no matter how good the helmet is at force attenuation, no matter what "accessories" also serve to attenuate force (the so-called "hard" mouth guard and "hard" chinstrap with six point security), and no matter how diligent coaches and players are regarding the use of "safe" or "proper" tackling techniques, the helmet cannot protect against all injuries, especially those due to rotational acceleration as it affects the brain. More on this issue next month.