A VISIT TO THE SHRINES OF THE VERTICAL JUMP AND THE 40 YARD DASH

Biomechanics has a unique focus in the study of sports. While other sports subdisciplines such as motor learning, exercise physiology, and sports psychology grapple with hypotheses and theories, biomechanics is in the enviable position of being rooted upon a well defined body of principles and laws. These have been passed on to us by some of the founding fathers of science itself. Included in their number are the disciples Aristotle, da Vinci, Borelli, Galileo, and Newton. Working with knowns and invariability makes it easy for the biomechanist to generalize. If the variables of the equation are known, then the outcome is certainly known. However, such a distilled view of human movement is not possible in the real world. The biomechanist must learn to cope with the inherent variability of human motor performance. This paper will discuss some of the problems encountered in making this transition. Specifically, misinformation regarding two increasingly used predictors of motor ability -the vertical jump and the 40 yard dash -will be explored. It would not be too much of an exaggeration to suggest that these two performances have become shrines of sort, worshipped by those who seek athletic deliverance. But, beware of false gods!