OpenSim: Open-Source Software to Create and Analyze Dynamic Simulations of Movement

Abstract

Abstract-Dynamic simulations of movement allow one to study neuromuscular coordination, analyze athletic performance, and estimate internal loading of the musculoskeletal system. Simulations can also be used to identify the sources of pathological movement and establish a scientific basis for treatment planning. We have developed a freely available, open-source software system (OpenSim) that lets users develop models of musculoskeletal structures and create dynamic simulations of a wide variety of movements. We are using this system to simulate the dynamics of individuals with pathological gait and to explore the biomechanical effects of treatments. OpenSim provides a platform on which the biomechanics community can build a library of simulations that can be exchanged, tested, analyzed, and improved through a multi-institutional collaboration. Developing software that enables a concerted effort from many investigators poses technical and sociological challenges. Meeting those challenges will accelerate the discovery of principles that govern movement control and improve treatments for individuals with movement pathologies.Index Terms-Computed muscle control, forward dynamic simulation, musculoskeletal modeling, open-source software.

Tibiofemoral contact forces during walking, running and sidestepping

“…Gait biomechanics were determined using OpenSim v3.2 [23]. A generic anatomic model ( Figure 1A), based on a previous study running of dynamics [24] was used.…”

Man/machine interface based on the discharge timings of spinal motor neurons after targeted muscle reinnervation

“…During the scaling process, virtual markers were placed on the generic musculoskeletal geometry model based on the position of the experimental markers from the static pose. The model anthropomorphic properties as well as the muscle-tendon unit insertion, origin and their bone wrapping points were linearly scaled on the basis of the relative distances between experimental and corresponding virtual markers 44 . Inverse kinematics was solved for three-dimensional joint angles that minimized the least-squared error between experimental and virtual marker locations during dynamic trials 46 .…”

Lower limb loading during knee up in step aerobics: a pilot study

“…Driving each musculotendinous unit is a first-order differential equation which couples neutral excitation to muscle activation [2]. The values of maximum isometric strength, optimal fibre length, pennation angle and tendon slack length for each actuator are based on data reported by Delp [9]. Where possible, the action of a muscle group is reported as a single line of force.…”