Biomechanical Comparison of Human Walking Locomotion on Solid Ground and Sand

TL;DR

This work addresses how granular terrain (sand) affects human walking biomechanics and provides a synchronized kinematic-kinetic dataset for solid ground versus sand using 20 healthy adults. It combines motion capture and ground reaction force measurements and applies inverse dynamics to quantify joint angles, moments, and stiffness across terrains. Key findings include longer and wider strides, altered joint kinematics with greater hip/knee flexion and ankle dorsiflexion on sand, and distinct GRF patterns reflecting energy dissipation on deformable substrates. The open dataset and analysis framework support terrain-adaptive rehabilitation devices and robotic locomotion, with opportunities to extend to more terrains and EMG integration.

Abstract

Current studies on human locomotion focus mainly on solid ground walking conditions. In this paper, we present a biomechanic comparison of human walking locomotion on solid ground and sand. A novel dataset containing 3-dimensional motion and biomechanical data from 20 able-bodied adults for locomotion on solid ground and sand is collected. We present the data collection methods and report the sensor data along with the kinematic and kinetic profiles of joint biomechanics. A comprehensive analysis of human gait and joint stiffness profiles is presented. The kinematic and kinetic analysis reveals that human walking locomotion on sand shows different ground reaction forces and joint torque profiles, compared with those patterns from walking on solid ground. These gait differences reflect that humans adopt motion control strategies for yielding terrain conditions such as sand. The dataset also provides a source of locomotion data for researchers to study human activity recognition and assistive devices for walking on different terrains.

Figures (10)

• Figure 1: Experimental platform design and setup inside a laboratory for human walking on solid and sand terrains.
• Figure 2: Schematic of the Vicon marker placement for the human lower limb segments. The markers were placed bilaterally.
• Figure 3: The distribution of step parameters for all participants combined (n = $20$) while walking on the two different terrains: solid ground (blue) and sand (yellow). The comparison was among the stride length, stride width, COM variation, walking velocity (all normalized with respect to participants' heights), swing, and stance time. Data included all strides for individual trials. The label $*$ indicates a significant ($p < 0.05$) difference among trials.
• Figure 4: Human walking gait comparison. The top and bottom rows represent the angles of the right and left leg, respectively. The first column: hip flexion(+)/extension(-); the second column: knee flx/extension; the third column: ankle dorsi(+)/plantarflexion(-).
• Figure 5: The comparison of the ground reaction forces on sand and solid ground. (a) Longitudinal forces $F_x$. (b) vertical/normal forces $F_z$.