ARE PROXY MEASURES VIABLE FOR THE ANALYSIS OF GAIT TERMINATION?
Gait termination is an important part of daily activity, both in planned and unplanned stopping instances. While planned stops are well understood thoroughly, unplanned stops cannot be truly studied in a traditional gait lab environment, where the stopping area is constrained above force plates. PURPOSE: The purpose of this study was to test proxy measures for commonly reported variables related to gait termination. METHODS: Nine able-bodied subjects (5M/4F, 27.4±6.9 yrs) completed this protocol. Subjects completed 10 successful planned stopping and 10 successful unplanned stopping trials on a 15m walkway. Success was defined as the subject coming to a staggered stop with the foot of the leading limb entirely on one force plate. Thirty percent of unplanned stopping trials did not include a stopping stimulus, to reduce subjects’ anticipation of the stopping stimulus. Data were collected from four in-ground force plates, plantar pressure insoles, and bi-lateral ankle-mounted accelerometers. Peak braking force (Fy) and anterior center of pressure (COPy) shift were calculated from ground reaction force (GRF) data. Fy data were normalized to subjects’ body weight. Plantar pressure COPy shift and peak anterior acceleration (Ay) were extracted for comparison with the GRF-related measures. Linear correlation analyses were performed between GRF COPy shift and plantar pressure COPy shift, and between peak Fy and peak Ay. RESULTS: COPy shift from GRF data and plantar pressure COPy shift for all subjects did not demonstrate a linear relationship (R2=0.01). There was wide variation across subjects, ranging from no relationship to strong relationship (R2 values from 0.00 to 0.75). Similar trends were observed in the relationship between peak Ay and peak Fy, with group R2=0.09 and individual R2 values ranging from 0.00 to 0.40. CONCLUSIONS: Based on this analysis, using accelerometry and plantar pressure insoles in place of commonly reported gait termination variables is not recommended due to both individual variation and measurement errors.
Ohm, K and Hahn, M
"ARE PROXY MEASURES VIABLE FOR THE ANALYSIS OF GAIT TERMINATION?,"
International Journal of Exercise Science: Conference Proceedings: Vol. 8
, Article 64.
Available at: http://digitalcommons.wku.edu/ijesab/vol8/iss3/64
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