EFFECTS OF SHOD AND BAREFOOT CONDITIONS ON MEDIAL LONGITUDINAL ARCH ANGLE DURING RUNNING

The structure of the medial longitudinal arch (MLA) affects the spring-like function of the foot and is crucial to running performance. The purpose of this study was to investigate the differences in the MLA angle between barefoot and shod conditions by using a high-speed dual fluoroscopic imaging system (DFIS). Computed tomography was taken of each participant’s right foot for the construction of 3D models and local coordinate systems. Fifteen participants ran with or without running shoes at 3 m/s±5% speed. We recorded foot kinematics using DFIS. After the process of 3D-2D registration, MLA angles were calculated. Compared to barefoot, wearing shoes 1) decreased the initial landing MLA angle, maximum MLA angle and range of motion of the MLA angle (p \u3c 0.05); 2) decreased the MLA angles during 0%-70% of the stance phase (p \u3c 0.05). It suggests that shoes limit the MLA compression and recoil and its spring-like function

EFFECTS OF SHOD AND BAREFOOT RUNNING ON THE IN VIVO KINEMATICS OF THE FIRST METATARSOPHALANGEAL JOINT

The purpose of this study is to investigate the differences of the first metatarsophalangeal joint’s 6 degree-of-freedom (6DOF) kinematics during shod and barefoot conditions by using a high-speed dual fluoroscopic imaging system (DFIS). Fifteen healthy male runners were recruited. Computed tomography (CT) scans were taken of each participant’s right foot for the construction of 3D models and local coordinate system. The fluoroscopic images of the right foot during the stance period were acquired under shod and barefoot condition with rearfoot strike pattern Radiographic images were acquired at 100 Hz while the participants ran at a speed of 3±5% m/s in a track and 6DOF kinematics were calculated by 2D-3D registration. Paired sample t-test was used to compare the kinematic characteristics of the first MTPJ 6DOF kinematics between shod and barefoot. Compared with barefoot, wearing shoes 1) decreased the peak medial, posterior, and superior translation of the first MTPJ during stance (P ＜ 0.05); 2) decreased maximum extension angle, minimum extension angle, and flexion/extension range of motion of the first MTPJ during stance (P ＜ 0.05); 3) increased minimum adduction angle of the first MTPJ during stance (P ＜ 0.05). It suggests that shoes may affect the function of the first MTPJ and increase the risk of hallux valgus. Our study makes up for the deficiency of traditional motion measurement methods that only focus on the sagittal flexion and extension movement of the first MTPJ and provides a more comprehensive understanding of the potential relationship between joint motion and injurie

Effects of different habitual foot strike patterns on in vivo kinematics of the first metatarsophalangeal joint during shod running—a statistical parametric mapping study

Existing studies on the biomechanical characteristics of the first metatarsophalangeal joint (1st MTPJ) during shod running are limited to sagittal plane assessment and rely on skin marker motion capture, which can be affected by shoes wrapping around the 1st MTPJ and may lead to inaccurate results. This study aims to investigate the in vivo effects of different habitual foot strike patterns (FSP) on the six degrees of freedom (6DOF) values of the 1st MTPJ under shod condition by utilizing a dual-fluoroscopic imaging system (DFIS). Long-distance male runners with habitual forefoot strike (FFS group, n = 15) and rearfoot strike (RFS group, n = 15) patterns were recruited. All participants underwent foot computed tomography (CT) scan to generate 3D models of their foot. The 6DOF kinematics of the 1st MTPJ were collected using a DFIS at 100 Hz when participants performed their habitual FSP under shod conditions. Independent t-tests and one-dimensional statistical parametric mapping (1-d SPM) were employed to analyze the differences between the FFS and RFS groups’ 1st MTPJ 6DOF kinematic values during the stance phase. FFS exhibited greater superior translation (3.5–4.9 mm, p = 0.07) during 51%–82% of the stance and higher extension angle (8.4°–10.1°, p = 0.031) during 65%–75% of the stance in the 1st MTPJ than RFS. Meanwhile, FFS exhibited greater maximum superior translation (+3.2 mm, p = 0.022), maximum valgus angle (+6.1°, p = 0.048) and varus–valgus range of motion (ROM) (+6.5°, p = 0.005) in the 1st MTPJ during stance. The greater extension angle of the 1st MTPJ in the late stance suggested that running with FFS may enhance the propulsive effect. However, the higher maximum valgus angle and the ROM of varus–valgus in FFS may potentially lead to the development of hallux valgus