Seeking To Make Youth Sports Safe - safety measures and standards for youth sports

USA Today (Society for the Advancement of Education), July, 2001 by P. David Halstead

In most cases, personal protective equipment grew out of a need, and the process often was simple. If you got hurt, you put some padding on the spot in the hope it would prevent further injury. If that did not work, you might add a hard shell over the padding in the form of a simple helmet, shoulder pad, shin pad, etc. In many instances, that is all that is needed.

In some areas of the body, however, a deep understanding of the biomechanics of an injury is called for. Head trauma is perhaps the best example.

There are at least two major causes of the closed head injuries suffered by athletes. One is triggered by linear acceleration and deceleration in a straight line, such as the sudden stop when a head hits the ground at the end of a fall.

The other type is rotational or angular acceleration. Perhaps the best example of this may be what has come to be called "shaken baby syndrome," which may result from shaking or rapidly routing the head--either side to side or up and down, or nearly any combination of the two. The causes of these injuries, whether in a baby or an adult, are so far not understood as well. Threshold injury values for linear acceleration are estimated with some degree of scientific certainty, but rotational injury is less well-documented. Work in that area is progressing, and a better understanding of threshold limit values might be forthcoming during the next several years.

In the typical serious head trauma, it is likely that both these injury mechanisms are present. From the protective equipment standpoint, this is a potential quandary. In the rotational type of injury, a helmet may be of little or no value. In fact, having the added mass of a helmet on your head may be a bad thing, depending on a variety of factors. For example, in a violent rotation like shaken baby syndrome, where there is no risk of head impact, but the head motion is very violent and variable in force and direction, the mass of the helmet on the head would tend only to increase the momentum and thus the damage to the brain. This, of course, assumes that the mass of the helmet is not sufficient to prevent the motion from being initiated in the first place. In the case of football, say, not having the helmet represents such a known and obvious risk from linear acceleration injury that you must wear one. Since a helmet that is there when you need it and not when you don't--a force field, so to speak--has not yet been designed, an understanding of the mechanics involved and the resultant tradeoffs that have to be made is required.

One such example is the "softer" baseball. It is true that softer baseballs that meet the NOCSAE standard reduce the risk of trauma should you be struck on your unprotected head by one at a high speed. Using this type of ball, however, may not affect the risk of commotio cordis, a sudden stopping of the heart due to an impact to the torso. It is even possible that, in some scenarios, a softer ball may be more likely to trigger this rare cardiac response than a harder ball would. Good research is being done in this area and seems to show that both ball speed and stiffness are relevant as causes for such an occurrence. For arguments sake, let us assume that, in some cases, the ball hitting the unprotected player's chest and causing a bruise or even a bone break may not be the type of impact that results in the cardiac cycle becoming upset. If so, we must assume that using a vest or softer ball may reduce the impact to the player, but, in doing so, might put that impact in the range that is most likely to cause cardiac arrest. If that proves to be correct, we must be careful not to turn the big bruiser impact into a smaller deadly one. With that said, the real issue may be the timing of the impact and, for that reason, until we know more, the softer ball is likely the best choice to reduce all types of injury for the youngest ballplayers.