Toe flexor strength is not related to postural stability during static upright standing in healthy young individuals.

Background: The human foot has adapted specifically to support body weight when standing upright. At the base of the postural control system, the unique arch structure of the foot still has an uncertain role in human upright standing. Because the toe flexor muscles help to support the foot arches, they might be an important contributor to postural stability. However, no research has identified the influence of the toe flexor strength or the foot arch height on postural stability in static upright standing.
Research Question: The aim of this study was to examine whether the toe flexor strength and the foot arch height were related to postural stability in static standing in healthy young individuals.
Methods: Fifty healthy young individuals were recruited into this cross-sectional study. Toe flexor strength was measured using a toe grip dynamometer, and it was normalised by body mass (rTFS). Foot arch height was assessed as the distance between the navicular tuberosity of the foot and the floor, and it was normalised by height (rFAH). Postural stability was evaluated using the path of the centre of pressure (COP) during double-leg standing with eyes open and single-leg standing with eyes open.
Results: rTFS and rFAH were 2.6 ± 0.8 N/kg and 2.8 ± 0.4%, respectively, and they were not significantly correlated (r = 0.094), indicating that they were independent variables. The results of Pearson's correlation analysis revealed that any body size related variables (height, body mass, BMI) were not significantly correlated with COP variables under either double-leg or single-leg standing, rTFS was not significantly correlated with COP variables under either double-leg or single-leg standing and rFAH was not significantly correlated with COP variables under double-leg standing.
Significance: Toe flexor strength has no significant role in maintaining postural stability during static upright standing.
(Copyright © 2019. Published by Elsevier B.V.)