Modeling and Simulation of Achilles Tendon in OpenSim for Verification

Abstract

Abstract The Achilles tendon is a very important tendon that is vital to an individual’s movement. Once these tendons are torn, they become very difficult to heal. In order to avoid this situation, it is crucial to understand the limitations of the Achilles tendon on the average person. To study the properties of an Achilles tendon, research can be done in many ways, such as data collection of in-vivo specimens. Although this can be done, using an online simulation can result in quicker and more accurate data. One program that can be used to create a simulation of an Achilles tendon is OpenSim. In this study 5 different subjects, both male and female with ages 22+/−5 years are studied. The subject will stand on one foot which is the maximum amount of weight on one leg and that Achilles Tendon. The forces will be calculated on that foot using sensors such as laser displacement sensors. The weight of the subject will cause the ground reaction and the magnitude of the tensile force which will be exerted by the gastrocnemius and soleus muscles on the calcaneus through the Achilles tendon will be calculated. The magnitude of the reaction force of the subject will be exerted at the ankle joint and it is applied by the tibia on the talus dome. The Achilles tendon is attached to the calcaneus bone and for this position of the foot, it is estimated that the line of action of the tensile force in the Achilles tendon makes an angle q (theta) with the horizontal, and the line of action of the ankle joint reaction force makes an angle b (beta) with the horizontal. We will use the force vectors to draw the concurrent diagram in order to find the unknown forces of the Achilles tendon and the tibia reactive force on the joint. By studying the properties of the Achilles tendon, while it is at 2 different dorsiflexed angles. These angles will vary from 0 degrees to 90 degrees. These concurrent force vector diagrams method will be applied to both configurations to find the unknown forces of the Achilles tendon and the tibia reaction on the dome of the talus. OpenSim is mainly used for biomechanical modeling and analysis of those models. The purpose of this research paper is to provide a comparison of data collected from real individuals and the simulation data from an OpenSim model.