Biomechanics of human passive muscles

Abstract

This project described the passive biomechanical properties of human gastrocnemius muscle-tendon unit, which is less understood in the literature. Currently most work has been done on the passive biomechanical aspect of human skeletal muscles only examined the elastic behaviour of human skeletal muscles, the effect of the viscous component was not considered. Therefore, the main aim of this project is to characterize the viscoelastic properties of human gastrocnemius muscle-tendon unit by using quasi-linear viscoelastic theory, and further to model both elastic and viscous behaviours of human gastrocnemius muscle-tendon unit in vivo under passive conditions. The research project consists of four interrelated studies, which include 1) characterize the viscoelastic properties of human gastrocnemius muscle-tendon unit by using quasi-linear viscoelastic theory; 2) characterize the stress-relaxation properties at the human ankle joint, which is important to be determined before applying quasi-linear viscoelastic theory; 3) review current techniques for estimating the muscle-tendon moment arm, and examine the validity of the measurement of gastrocnemius muscle-tendon moment arm length used in this project; 4) explore the intermuscular force transmission between the human medial gastrocnemius muscle-tendon unit and soleus muscle-tendon unit in vivo under passive conditions, which examine the validity of the assumption made in this project.