Arnold, E.M., Ward, S.R., Lieber, R. L., and Delp, S.L., A model of the lower limb for analysis of human movement, Annals Biomedical Engineering 2010 Feb;38(2):269-79. Epub 2009 Dec 3. (2010)
Abstract    View

Computer models that estimate the force generation capacity of lower limb muscles have become widely used to simulate the effects of musculoskeletal surgeries and create dynamic simulations of movement. Previous lower limb models are based on severely limited data describing limb muscle architecture (i.e., muscle fiber lengths, pennation angles, and physiological cross-sectional areas). Here, we describe a new model of the lower limb based on data that quantifies the muscle architecture of 21 cadavers. The model includes geometric representations of the bones, kinematic descriptions of the joints, and Hill-type models of 44 muscle-tendon compartments. The model allows calculation of muscle-tendon lengths and moment arms over a wide range of body positions. The model also allows detailed examination of the force and moment generation capacities of muscles about the ankle, knee, and hip and is freely available at .

Provide models that can estimate force and moment generating capacity of the lower limb and reveal relationships between muscle architecture and function.

License: 2-Legs and Torso, OpenSim, Single Leg SIMM Versions

Our paper describes a musculoskeletal model of the lower limb based on experimental measurements of muscle architecture in 21 cadavers. This model is related to the model described by Delp et al. (1990) but corrects several known inaccuracies and is more versatile due to the availability of new data describing muscle architecture that relates fiber length and joint angle.

The model provides accurate representations of muscle moment arms and force generation capacities and allows detailed examination of the moment generation capacities of muscles about the ankle, knee, and hip.


This project contains all the files necessary for the SIMM and OpenSim versions of the model of the lower limb described in our publication. For the SIMM version the .msl and .jnt files contain detailed comments regarding the differences between this and prior models; relevant publications for citation; and sources for architecture parameters.
For the OpenSim version this information is contained in the .osim file or can be viewed in the GUI by right-clicking on the model name in the navigator and selecting "Info."

In order to respect the time and effort put in by the original developers, and to avoid exceeding the limitations of the model, please read the accompanying publications and cite appropriate references.

These files can be imported into and used in OpenSim. Please see for more information on OpenSim.

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