Modelling Short-Range Stiffness

Modelling Short-Range Stiffness: Comparison Between Hill- and Huxley-type Muscle Models

Franzen, Thijs (TU Delft Mechanical, Maritime and Materials Engineering; TU Delft Biomechanical Engineering)

van der Helm, Frans (mentor)
Mugge, Winfred (mentor)

Delft University of Technology

2019-08-30

Musculoskeletal models often use Hill-type models to study and simulate muscle behaviour. Due to fast simulation time and ability to simulate large and slow movements Hill-type models have remained largely unchanged throughout recent years. Large and slow movements spend a large part in steady state behaviour and thus experience limited influence of transitional behaviour. However, during small and fast movements, transitional behaviour has more influence and causes inaccuracies in Hill-type models, which can cause an overestimation of muscle force. One characteristic of transitional behaviour is short-range stiffness (SRS). This property is a result of crossbridge dynamics and causes an increase in stiffness when muscle velocity changes. Huxley-type models are capable of simulating transitional behaviour, but are computationally expensive. The goal of this article is to identify the optimal parameter values for two Hill- and one Huxley-type model using a surrogate optimization algorithm and determine if these models can simulate general behaviour and SRS. The parameters are fitted to one soleus and medial gastrocnemius muscle of a cat. All models were able to simulate the experimental data with an average RMS of 6.6N and 4.8N for the Hill models and 5.5N for the Huxley model. However, all three models were not capable of predicting SRS during isometric contractions and the method of determining SRS during non-isometric contractions proved unusable. Thus, the Huxley model that was used had no advantage over the used Hill-type muscle models. Furthermore, it was concluded that the simplest Hill was the only model viable for real-time application.

short-range stiffness
Hill
Huxley
Skeletal muscle
muscle model
Cat

http://resolver.tudelft.nl/uuid:037d8aca-6826-42ec-b9d0-42cb31961404

Student theses

master thesis

© 2019 Thijs Franzen