Analysis of medial deviation of center of pressure after initial heel contact in forefoot varus

• Main Author: Wei-Li Hsi
• Format: Article
• Language: English
• Published: Elsevier 2016-03-01
• Series: Journal of the Formosan Medical Association
• Subjects: biomechanical phenomena; foot; heel; weight-bearing
• Online Access: http://www.sciencedirect.com/science/article/pii/S0929664615001321

After initial heel contact, the rearfoot everts and causes medial deviation of the center of pressure (CoP). Although rearfoot angle in single-limb stance has been associated with forefoot varus (FV) ≥ 8°, medial CoP deviation has not. Methods: After 12 participants with FV < 8° (neutral group) and 11 participants with FV ≥ 8° (FV group) stepped one heel initially onto an array of pressure sensors parallel to its Y coordinate axis, when the CoP of array deviated most medially, the X coordinate of the CoP of each row was calculated to find the most medial CoP of the row. Starting since the row with the most medial CoP just began to have the same sensors with pressures >0 kPa as when it had the most medial CoP, the medial deviations of the CoP of the array, the most medial CoP of the row, and its relative position in the row (CoP%), were compared between neutral and FV groups. Results: The medial deviations of the most medial CoP of the row (1.1 ± 0.6 vs. 1.6 ± 0.3 mm, p = 0.049) and CoP% (2.9 ± 1.4 vs. 4.2 ± 1.1%, p = 0.023) were significantly different between neutral and FV groups, whereas that of the CoP of the array (1.1 ± 0.6 vs. 1.4 ± 0.6 mm, p = 0.36) was not. Conclusion: The most medial CoP of the row and CoP% detected increased medial CoP deviation in FV ≥ 8°, and may be applied to other clinical conditions where rearfoot angle and CoP of the array after initial heel contact cannot detect significant differences.