Novel Experimental System And Method For Measuring Tri-axial Force On Foot-Ground Interface

Measurement of the tri-axial force on foot-ground interface is a way of acquisition of the most comprehensive information in the plantar, which facilitates the human-body modeling of movement and may enhance the effect of sports training, improve sports technical movement, and reduce sports injuries. At present, the main methods for measuring tri-axial force on foot-ground interface include the tri-axial force plates and force measurement shoes and insoles. Tri-axial force plates measure the tri-axial force on foot-ground interface, but they are large and heavy. So they can only measure gait parameters of the standing position or a step of walk, thus limiting their application. The force measurement shoes and insoles can only measure the vertical stresses between the foot and ground, and they are not applicable in high-intensity sports and exercise. Therefore, currently available methods for measurement of the tri-axial force on foot-ground interface have drawbacks. A novel experimental system and method is proposed in this paper for measuring the tri-axial force on foot-ground interface in human-body movement, providing guidance and assistance for sports training and scientific research.In sprint,the starting action with reasonable and coherent movement is very important. An effective starting action depends on the tri-axial force on foot-ground interface, the location of the starting blocks, the angles of articulations, and other factors. In order to improve the movements in the starting action, a new method using AnyBody numerical simulation is proposed to verify aforesaid measurement system of the tri-axial force on foot-ground interface. Based on AnyBody, a simulation model of the starting action is presented, which is evaluated by calculation of the forces in each bone, muscle and articulation.Spiked shoes for the tri-axial force measurement are then proposed and designed for experiments of studying the starting motion. The spiked shoes for tri-axial force measurement are composed of three parts: (1) a novel tri-axial force measurement device for measuring tri-axial force on foot-ground interface; (2) the data acquisition system; (3) the part of signal processing by computer. The tri-axial force measurement spiked shoes have achieved three functions: (1) transformation of the tri-axial force on foot-ground interface to electrical signals; (2) acquisition and storage of the data; (3) display of the data files saved in computer.In order to check the output characteristics of tri-axial force measurement device, we have designed dynamic loading test experiments. Based on the second-order nonlinear model of the impact machine system, a dynamic loading test equipment to simulate the impact on the foot-ground interface is developed to validate the tri-axial force measurement device. The experimental curves and the theoretical calculation results show good consistency.In this paper, the sport biomechanics analysis is carried out for the crouch starting, and it uses AnyBody for modeling simulation. The spiked shoes for tri-axial force measurement are proposed, designed and used for experiments by changing the starting block's angles and positions. In the experiment, the AnyBody modeling simulation is incorporated into a complete experimental platform, which provides a new method for measuring tri-axial force on foot-ground interface and may be helpful for improvement of athletes'running speed. In the future, the method may be introduced in sports training to help athletes'master technical key-points of the sports training technical essentials, and improve training efficiency.