Dynamic visual acuity in sports performance



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Sports involving high velocity moving targets are common at all levels of athletic competition. Success in these sports requires a physically fit competitor and extensive practice but there could also be a strictly visual component in the formula for success. Eye movements that track high velocity targets in certain sports are the same as the eye movements that are an important component of dynamic visual acuity (DVA). The purpose of this investigation is twofold: (1) Determine whether DVA could distinguish the competitive athlete from the average sportsman, and (2) Determine whether a significant relationship exists between the athlete's performance and DVA. Baseball is a sport that requires visual tracking of high velocity targets and one of the most difficult skills in sports is to hit a pitched ball. Baseball also has a statistical convention for measuring a player's hitting success that can be used as the metric of performance. Therefore, DVA was measured for baseball players and compared to their hitting statistic. The sample consisted of an experimental group of 27 varsity baseball players from the University of Houston and 38 control subjects. Threshold DVA was assessed by the method of constant stimuli using 4- position Es. Each subject was tested at five different angular velocities ranging from 30 deg/sec to 150 deg/sec. The stimuli were visible through 120 deg of visual field. The results show that the experimental group had significantly superior DVA when compared to the control group at all test velocities (p < 0.0025 on a one-tail t-test). For ten experimental subjects with forty or more times at bat, significant linear relationships were found between 150-deg/sec DVA and batting averages (p < 0.11) as well as slugging averages (p < 0.075). It is concluded from these results that varsity baseball players are part of a select population resistant to reductions in visual acuity with increasing velocity of targets in the range of 30 to 150 deg/sec. In addition, DVA threshold may be predictive of J certain kinds of athletic potential.



Visual acuity, Baseball--Physiological aspects