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Published on: August 30, 2016
Center of pressure excursion capability in performance of seated lateral-reaching tasks
M B Parkinson1, D B Chaffin, M P Reed
1Engineering Design, The Pennsylvania State University, 213 Hammond Building State College, 16802, USA. parkinson@psu.edu
Background:
Seated center of pressure excursion capability can be used for patient evaluation in a clinical setting and in universal design. A quantification of excursion capability across age and anthropometry has not been previously reported, although some research suggests that the ischial tuberosities are the support structure limiting the excursion.
Methods:
Thirty-eight neurologically healthy adults ranging in age from 21 to 74 years and including 12 obese persons performed a series of 6 lateral-reaching tasks. Participants sat on a platform such that their feet did not touch the ground, leaving their legs free to provide counterbalancing support. Data recorded from a force plate under the platform allowed calculation of the center of pressure throughout the trial and the maximum excursion for each condition was recorded.
Findings:
The average excursion capability for the healthy, experimental population was 148 mm or 37% of seated hip breadth. Taller participants had larger maximum excursions, on average, than shorter participants, and older participants had smaller excursions than younger participants.
Interpretation:
The greater trochanter of the femur-rather than the ischial tuberosities-appears to be the primary support structure limiting center of pressure excursion in lateral, balance-limited reaches without contralateral support. These measures and concepts can be used for design, accommodation, and clinically for patient assessment.
