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Nick Fogt, Tyler Persson; Vertical rotational gaze tracking errors in baseball batting. Invest. Ophthalmol. Vis. Sci. 2018;59(9):2163.
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The accuracy of ocular gaze tracking of pitched baseballs may impact on hitting performance. Horizontal (rotational) gaze tracking data have been published. Horizontal gaze is maintained on the ball until late in the pitch trajectory when batters swing at pitches, while horizontal gaze is placed ahead of the ball late in the pitch when batters “take” (no intention to swing) pitches. The purpose of this report is to describe vertical gaze tracking rotations (obtained simultaneously with previously reported horizontal data) in baseball batting and to compare these rotations to those when batters “take” pitches.
Two young males who had previously played college baseball participated. The participants viewed tennis balls “thrown” from a pneumatic pitching machine (75mph). The balls followed a parabolic trajectory. In one condition (swing), participants attempted to bat the balls while in a second condition participants acted as if they were “taking” pitches (“take”). Vertical eye rotations were monitored with a video eye-tracker and vertical head rotations were monitored with a magnetic tracker. Eye rotation, head rotation, and ball locations were synchronized.
Vertical gaze tracking data (eye rotation plus head rotation) were examined at 9 elapsed times of interest (150-512ms) after pitch release. 25 (“take”) and 23 (swing) pitches were analyzed for one participant and 13 (“take”) and 13 (swing) pitches were analyzed for the other participant. Results from the two participants were averaged. In both the “take” and swing conditions (downward) head rotations were larger than (downward) eye rotations late in the pitch. In the “take” condition, mean vertical gaze errors were less than 1 deg at elapsed times up to and including 450ms (at which point the ball was about 5 feet from the batter) and then increased substantially to values >20deg. In the swing condition, vertical gaze errors were small (<6deg below the ball). Vertical gaze errors after 450ms then increased substantially (>25deg) in the swing condition.
Vertical gaze errors in the two conditions were relatively small in both the “take” and swing conditions up to and including elapsed times of 450ms. This is different from horizontal rotations, where gaze was directed ahead of the ball late in trajectory in the “take” condition but not in the swing condition. In the swing condition, there was a mild tendency to place vertical gaze below the ball.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.
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