The Examination of the Patterns of Bi-lateral Ground Reaction Forces During Quiet Standing

Open Access
Meholic, Bradley Steven
Area of Honors:
Bachelor of Science
Document Type:
Thesis Supervisors:
  • John Henry Challis, Thesis Supervisor
  • Jinger S. Gottschall, Honors Advisor
  • Dr. Gary L Gray, Honors Advisor
  • Judith A Todd Copley, Faculty Reader
  • posture
  • standing
  • postural stability
  • entropy
  • center of pressure
  • postural control
  • quiet standing
The main purpose of this study was to determine the degree of lower limb independence and relatedness during quiet standing. Nine healthy young adults (5 females, 4 males; 22 ± 1 year; 1.69 ± 0.08 m; 73 ± 13 kg) stood with one foot on each of two separate force plates where they performed three eyes-open and three eyes-closed quiet standing trials. Various traditional center- of-pressure (COP)-based measurements were made in order to determine if the subject pool demonstrated postural dynamics typical of healthy young adults. The focal point of the study, however, were the approximate entropy (ApEn) measurements, which were used to ascertain the orderliness of the vertical ground reaction forces created under each foot. Data were typical when assessed using traditional measures of COP motion. Results of the ApEn measures suggested that the left leg and right leg are controlled independently of each other during quiet standing. The findings of this study will be useful to researchers and clinicians who are interested in learning more about the possible control mechanisms employed during quiet stance. Added knowledge to the field will optimistically lead to improved balance therapies and evaluation tools.