East Carolina University : Research and Creative Achievement Week 2012
relative force tests. These results may be influenced by the small sample size or inaccuracies with the eye tracker equipment. After collecting more subject data we will continue to calculate and analyze the correlation between force steadiness and visual steadiness in young. Absolute Muscle Force Steadiness and Visual Steadiness in Young Adults, Kathryn Reynolds, Luke Spangler, Rebecca Krupenevich, Patrick Rider, Dr. Nicholas Murray, Dr. Paul DeVita, Department of Kinesiology, East Carolina University, Greenville, NC 27858 The ability to exert steady muscle forces is critical for accurate neuromuscular function. Past studies showed that reduced muscle force steadiness was based on visual stimuli. Therefore the ability to visually perceive the stimuli may affect the muscle force output. We hypothesized that there was a direct relationship between muscle force steadiness and visual steadiness. The purpose of this preliminary study was to identify the relationship between muscle force steadiness and visual steadiness in young adults all adults exerted the same absolute muscle force. In this preliminary data set, four healthy subjects performed three vision dependent force tasks using eye tracker glasses and a dynamometer. For each task, the target or peak torque (directly proportional to muscle force) was set at an absolute value of 54 Nm. The first test required participants to contract the quadriceps isometrically at a constant target force of 54 Nm for 8 seconds. The second test involved isometric quadriceps contractions increasing from 0 Nm to 54 Nm and then decreasing to 0 Nm in a linear manner. The third test, like the second, involved quadriceps contractions increasing from 0 Nm to 54 Nm and then decreasing to 0 Nm in a parabolic curvilinear manner. Subjects controlled muscle force based on visual feedback by viewing the vertical position of an icon on a computer monitor that was proportional to the force. After collecting preliminary data from four young adults, we calculated and analyzed the relationship between force steadiness and visual steadiness. Only the parabolic test showed a direct relationship between muscle and visual steadiness. Whereas the other two tests surprisingly showed inverse relationships. These preliminary data did not strongly support our hypothesis that there is a direct relationship between muscle force steadiness and visual steadiness when all subjects performed at the same force level. This may be in part due to the small sample size or inaccuracy in the eye tracking glasses.
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