Influence of the Parameters of a Human Triceps Surae Muscle Model on the Isometric Torque-Angle Relationship

• Published in: Journal of biomechanical engineering 1996-02, Vol.118 (1), p.17-25
• Main Authors: Out, Lia, Vrijkotte, Tanja G. M, van Soest, Arthur J, Bobbert, Maarten F
• Format: Article
• Language: English
• Subjects: Ankle - physiology; Biological and medical sciences; Elasticity; Fundamental and applied biological sciences. Psychology; General aspects; Humans; Isometric Contraction - physiology; Knee Joint - physiology; Mathematics in biology. Statistical analysis. Models. Metrology. Data processing in biology (general aspects); Models, Biological; Muscle, Skeletal - physiology; Sensitivity and Specificity
• ISSN: 0148-0731; 1528-8951
• DOI: 10.1115/1.2795940

This study investigates the influence of parameter values of the human triceps surae muscle on the torque-angle relationship. The model used consisted of three units, each containing a contractile, a series elastic and a parallel elastic element. Parameter values were based on morphological characteristics, which made it possible to model individual units. However, for a number of parameters the values reported in the literature vary considerably. It was investigated how sensitive model results were for variation of these parameters. Slack length of the series elastic element, mean moment arm, maximum force, and length of the contractile element appeared to be the most important determinants of the behavior. For mean moment arm and contractile element length, morphology-based methods of estimation could be recommended. Slack length and maximum force were obtained through optimization. It was concluded that the model does not contain parameters on which its output depends strongly and which are difficult to estimate as well, with two exceptions: slack length of the series elastic element and maximum force.