@article{ref1,
title="Out of bounds in (American) football: player exposure to probability of collision injury",
journal="Journal of safety research",
year="1977",
author="Collins, GS and Garrick, J. G. and Requa, R. K.",
volume="9",
number="1",
pages="34-38",
abstract="One preventable football injury seldom studied is that resulting from a collision with a fixed peripheral obstacle.  In order to estimate the probability of collision by location and distance from the periphery of the playing field, a total of 81 game films were viewed and each player going out of bounds was charted by function (ball-carrier or non-ball-carrier), point at which he left the field, and distance traveled out of bounds.  A convenience sample of games showed the frequency of excursion to be greater nearer at the center of the field, although the distance traveled out of bounds did not vary appreciably by field location.  These findings suggest an appropriate buffer zone about the periphery of an athletic field.  For the games observed, and 18 foot (5.49 m) zone all our round the field contained 95% of the excursions and thus, if clear, would exclude 95% of potential obstacles for player collisions.<p />",
language="en",
issn="0022-4375",
doi="",
url="http://dx.doi.org/"
}