A comparison of kinematic and kinetic characteristics of intrinsic flexor muscles of the foot exercises: Effect on the medial longitudinal arch of the foot

Background Standing toe curl (STC) has an immediate effect on muscle activity, but the kinematics of the exercise and its effect on the medial longitudinal arch of the foot are unknown. Objective The purpose of this study was to examine the differences in kinematic and kinetic changes during toe flexion while performing towel curl (TC) in a standing position and STC. Methods Ten healthy adults with normal feet (18 limbs) participated in this study. Using a three-dimensional motion analysis system, we calculated the toe flexion angle, medial longitudinal arch (MLA) angle, MLA height, MLA length, ankle joint angle, center of foot pressure, and center position of the hip joint during toe flexion using TC and STC exercises. Results The TC exercise resulted in a decrease in the MLA due to the backward shift in the center of pressure and ankle dorsiflexion. On the other hand, STC did not demonstrate any significant difference in the position of the center of pressure or ankle joint angle, allowing the toes to flex while maintaining a standing posture and resulting in an increase in the MLA. Conclusions STC was suggested to be effective in maintaining MLA for weight support.