Kinematic analysis during toe-gripping strength exertion: angular changes in the ankle joint and leg muscle activities

Abstract

[Purposes] To investigate angular changes in the ankle joint and leg muscle activities during toe-gripping, and to examine the relationship between these changes and toe-gripping strength. [Subjects] Eleven healthy young women were selected. [Methods] We measured the toe-gripping strength, angular changes in the ankle joint, and leg muscle activities of all patients during toe-gripping. [Results] The mean change in the ankle angle in dorsiflexion from a neutral position was 3°, and a positive correlation was observed between this angle and toe-gripping strength (r = 0.61). Thus, toe-gripping strength increased with the angle of dorsiflexion. Regarding the leg muscle activities, activities of the tibialis anterior muscle and medial head of the gastrocnemius muscle demonstrated positive correlations with toe-gripping strength (r = 0.75 and r = 0.72, respectively). [Conclusion] These findings suggest that the ankle dorsiflexes in order to exert great toe-gripping strength, and the crural muscles contract simultaneously because of ankle fixation.

Examinations of factors influencing toe grip strength

“…As described by Murata6 ) , Uritani7 ) and Souma8,9,10,11 ) , the toe grip strength of the dominant foot, angular changes in the ankle joint during toe grip, maximum voluntary contraction (MVC) activities of the rectus femoris, biceps femoris, tibialis anterior, and medial head of the gastrocnemius muscles, toe curl ability, foot-arch height ratio, and weight were measured. Electrogoniometer and EMG activities were synchronously recorded during toe grip.…”

“…The subjects were instructed to sit with their trunk in a vertical position, to place their hip and knee joints at 90°, and to keep their ankle joints in the neutral position7,8,9,10 ) . The handle of the force meter was set on the first metatarsophalangeal joint.…”

“…An electrogoniometer (EM-551; Noraxon Inc., Scottsdale, AZ, USA) was attached to the inside of the lower leg over the center line, and the plantar surface of the toe was used10 ) . When achieving maximum voluntary isometric contraction of the rectus femoris, biceps femoris, tibialis anterior, and medial head of the gastrocnemius muscles, the level of exertion of muscular activity may vary depending on each joint angle.…”

“…For the rectus femoris muscle, an electrode was attached to the midpoint between the superior edge of the patella and the anterior superior iliac spine. For the long head of the biceps femoris muscle, an electrode was attached to the skin at the midpoint between the head of the fibula and ischial tuberosity10 ) .…”

“…They reported that the crural muscles help the ankle joint by co-contracting during toe grip, and that the activity of the tibialis anterior muscle plays a specific and important role. Souma et al10 ) performed a kinematic analysis of angular changes in the ankle joint and compared the results with the percentage of integrated electromyography (%IEMG) of the leg muscle activities during toe grip. They reported that the mean change in the ankle angle in dorsiflexion from a neutral position was 3°, and a positive correlation was found between this angle and toe grip strength.…”