Effects of Barefoot and Shod on the In Vivo Kinematics of Medial Longitudinal Arch During Running Based on a High-Speed Dual Fluoroscopic Imaging System

Abstract

Shoes affect the biomechanical properties of the medial longitudinal arch (MLA) and further influence the foot's overall function. Most previous studies on the MLA were based on traditional skin-marker motion capture, and the observation of real foot motion inside the shoes is difficult. Thus, the effect of shoe parameters on the natural MLA movement during running remains in question. Therefore, this study aimed to investigate the differences in the MLA's kinematics between shod and barefoot running by using a high-speed dual fluoroscopic imaging system (DFIS). Fifteen healthy habitual rearfoot runners were recruited. All participants ran at a speed of 3 m/s ± 5% along with an elevated runway in barefoot and shod conditions. High-speed DFIS was used to acquire the radiographic images of MLA movements in the whole stance phase, and the kinematics of the MLA were calculated. Paired sample t-tests were used to compare the kinematic characteristics of the MLA during the stance phase between shod and barefoot conditions. Compared with barefoot, shoe-wearing showed significant changes (p < 0.05) as follows: 1) the first metatarsal moved with less lateral direction at 80%, less anterior translation at 20%, and less superiority at 10-70% of the stance phase; 2) the first metatarsal moved with less inversion amounting to 20-60%, less dorsiflexion at 0-10% of the stance phase; 3) the inversion/eversion range of motion (ROM) of the first metatarsal relative to calcaneus was reduced; 4) the MLA angles at 0-70% of the stance phase were reduced; 5) the maximum MLA angle and MLA angle ROM were reduced in the shod condition. Based on high-speed DFIS, the above results indicated that shoe-wearing limited the movement of MLA, especially reducing the MLA angles, suggesting that shoes restricted the compression and recoil of the MLA, which further affected the spring-like function of the MLA.

Keywords: barefoot; dual fluoroscopic imaging system; in vivo kinematics; medial longitudinal arch; shod.

FIGURE 1

Reconstruction of the first metatarsal, navicular, and calcaneus.

FIGURE 2

High-speed DFIS set-up. Participants ran on an elevated platform. Image intensifiers (II#1 and II#2) processed images created by X-rays from the radiographic emitters (RE#1 and RE#2).

FIGURE 3

3D–2D registration. Bone positions were adjusted by translation and rotating the bone models in the software until the edge of the bones matched with the radiographic images.

FIGURE 4

First metatarsal (left) and calcaneus (right) motion diagram.

FIGURE 5

Bones and landmarks defining the MLA angle (θ).

FIGURE 6

6DOF movement of the first metatarsal relative to the calcaneus during the stance phase. *: significant differences between the shod and barefoot conditions, p < 0.05.

FIGURE 7

Peak translation and rotation of the first metatarsal relative to calcaneus in shod and barefoot conditions. *: significant differences between the shod and barefoot conditions, p < 0.05.

FIGURE 8

MLA compression and recoil during the stance phase. *: significant differences existed between the shod and barefoot conditions, p < 0.05.

FIGURE 9

Maximum and minimum MLA angles in shod and barefoot conditions. *: significant differences existed between the shod and barefoot conditions, p < 0.05.