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. The results reveal significant gait adaptations to the yielding terrain (i.e., sand), such as increased stance duration, reduced push-off force, and altered joint angles and moments. Specifically, the knee angle during the gait cycle on sand shows a delayed peak flexion and an increased overall magnitude, highlighting an adaptation to maintain stability on yielding terrain. These adjustments, including changes in joint timing and energy conservation mechanisms, provide insights into the motion control strategies humans adopt to navigate on yielding terrains. The dataset, containing synchronized ground reaction forces (GRFs) and kinematic data, offers a valuable resource for further exploration in foot-terrain interactions and human walking assistive devices development on yielding terrains.