Agenda : January 27th 8:30 – 9:00 Verify your Opensim installation 9:00 – 9:30 Introducing faculty and participants Ilse Jonkers & Friedl De Groote 9:30 – 10:00 Musculoskeletal modeling in Opensim - Use and application Ilse Jonkers 10:00 – 10:30 Data import, marker set definition, and scaling Marjolein van der Krogt 10:30 – 11:00 Coffee 11:00 – 13:00 Work on your own project 13:00 – 14.00 Lunch 14:00 – 14:30 Inverse Kinematics Friedl De Groote 14:30– 16:00 16:00-16:30 16:30-17:00 Inverse Dynamics Giordano Valente 17.00-18.00

Good morning and thank you all for coming Good morning and thank you all for coming. It’s wonderful to see every one here at the opening workshop. The goal of the opensim project is to provide advanced simulation tools to the worldwide biomechanics community so that we can better work together to advance mobility research and improve human health. My name is Scott Delp. I am a professor of BioE and orthopaedics at SU and I’m very pleased to be here with my colleagues to lead this workshop. Let me begin by thanking professor Ilse Jonkers (+ other names) for helping us organize the workshop. Let me also introduce Dr. Jen Hicks, Ajay Seth, Ayman Habib, Sam Hamner, Kat Steele, all simulation experts who will assist with the workshop. We all know that maintaining mobility is essentail for health and happyness. We also know that understanding human movement is complex, and engineering simulations of movement complement experimental approaches to biomehanics. http://opensim.stanford.edu

Elements of a Musculoskeletal Simulation Underlying the GUI is a set of algorithms that represent the dynamics of the musculoskeletal system. This diagram shows the key elements that for generating and simulation human movement. Review briefly. Over the next few slides I’ll give some more details. OpenSim includes musculotendon models that are based on testing against experimental data to match physiological musculotendon dynamics OpenSim also has mechanically-correct skeletal dynamics. You can model simple or highly complex joints. OpenSim also has sophisticated control algorithms. There are algorithms to create muscle driven simulations that track known motions you’ve measured in an experiment. We are also working on adding controllers that can synthesize new motions, without motion capture data. Or add your own controllers (e.g. simple reflex) In the software you can combine these elements to generate fast, accurate, muscle-driven simulated movements.

Purpose of modeling and simulation Visualize complex movement patterns Probe parameters that are difficult to measure Dynamic simulations of movement complement experimental approaches by providing estimates of important variables, such as muscle and joint forces, which are difficult to measure experimentally. Simulations also enable cause-effect relationships to be identified and allow “what if?” studies to be performed in which, for example, the excitation pattern of a muscle can be changed and the resulting motion can be observed. Perform “what if” studies Identify cause-effect relationships

Visualize human running in detail Created by PhD candidate, Samuel Hamner, this simulation tracks experimental measurements of surface markers positions and ground reaction forces from force-plates during treadmill running. We can observe the coordination of muscles during running.

Probe the function of a muscle Soleus (calf muscle) accelerates the mass center upward and forwards in mid-to-late stance We can plot the acceleration vector as rays at different instances in time during stance …

OpenSim is an application To model and visualize musculoskeletal structures, subject to the laws of physics and empirical evidence, to generate simulated movement. Be able to run analyses and plot results to gain insights into human and animal movement.

OpenSim is a modeling platform Deformation-Based Contact Forces Hunt-Crossley for analytical shapes Elastic foundation for an arbitrary mesh Contact is vital for synthesizing new motion. (e.g. no experimental ground reaction force data) OpenSim provides two types of contact forces: HC: uses analytical shapes that is efficient to solve EF: is mesh-based with an elastic element at the centroid of every face In both cases, you can set stiffness and dissipation to match material properties.

OpenSim is a modeling platform Muscle Actuators OpenSim also provides Muscle actuators. Muscles can include Complex paths that wrap around a variety of geometries. The models of muscle force production includes: excitation to activation dynamics tendon compliance and Hill type contractile elements. Not just muscles in OpenSim - can also represent other actuators (e.g. powered assistive device).

OpenSim is a modeling platform Controllers Controllers from simple to complex. This video shows a simple stretch-based reflex controller that we’ll use in the exercise.

OpenSim is a set of tools Importing and Previewing Motion Data OpenSim is also a set of tools for studying motion and generating simulations. I’ll quickly review. GUI shown here – also Matlab and C++ environments Preview motion capture data and grf force to make sure preprocessing was done correctly , data is in agreement with your model

OpenSim is a set of tools Scaling Musculoskeletal Models Scale tool—alter model anthropometry so it matches your experimental data as closely as possible.

OpenSim is a set of tools Inverse Kinematics and Inverse Dynamics Inverse Kinematics and Inverse Dynamics: step through time to determine the joint kinematics, net forces and/or torques at each joint in your model

OpenSim is a set of tools Estimation of Muscle Forces: Static Optimization and Computed Muscle Control Beyond net joint moments: estimate the muscles forces that drive a model’s motion. Solve muscle redundancy using the SO tool or CMC

OpenSim is a set of tools Forward Dynamics Once you have a set of controls, like muscle excitations, or if you have a controller, then can create a forward simulation of movement. Integrate forward in time using the underlying equations of motion of the model.

OpenSim is a set of tools Analyses: Induced Accelerations and Joint Reactions OpenSim also has tools to analyze a model or simulation. For example—built in tools to perform an induced acceleration analysis, joint reactions analysis. How do individual muscles contribute to motion? What are the joint reaction loads associated with a movement?

OpenSim is an extensible software framework OpenSim Graphical User Interface (GUI) Applications GUI Scripts Matlab Scripts Command Line Tools C++ Plugins OpenSim Modeling and Simulation Libraries OpenSim Application Programming Interface (API) Many researchers might just need the built in features accessible with the GUI, but if not you can extend OpenSim using the API (application programing interface) API is the set of libraries that define the models and algorithms I described in the last few slides. GUI uses the API. Can also write matlab scripts or plugins in C++ that extend the built-in functionality of OpenSIm Simbody Dynamics Engine SimBody API

OpenSim is a resource http://opensim.stanford.edu

OpenSim is a worldwide community

OpenSim is a team of contributors: Scott Delp Ayman Habib Jennifer Hicks Jeff Reinbolt Ajay Seth Michael Sherman Edith Arnold Matt DeMers Sam Hamner Chand John Kat Steele Melanie Fox Peter Eastman Clay Anderson Allison Arnold Eran Guendelman May Liu Peter Loan Darryl Thelen You!

Welcome! Find your group: Hip Thalia Kindt Iain Hannah CP Filipa Joao Antonio Veloso Patricia Mota Lizeth Slooth Lynn Bar-on Mirjam Niklash Teresa Martin Marta de Loma-Ossoria Garcia Tessa Hoekstra Antoine Falisse Sports Penny Hudson Neil Bezodis Ellen Maas Jeroen Aeles Knee Norbert Kapinski Jan Henriksson Josh Champion Cedric Schwartz Sara Marreiros Methods - Workflow Ursula Trinler Mathieau Menard Christian Silva Cedric Devivier Junfen Shi Kevin Tanghe Amber Bruijnes Tiago Malaquias If you feel you belong to another group, feel free to change! What data will you working on? Upper Limb Patrick Fasbender Benjamin Dourthe

Objectives for the Workshop Gain more insight in the Opensim workflow using your own motion capture data: Learn the underlying theory, best practices, and trouble shooting tips for IK, RRA and CMC through hands-on practice Learn techniques for data management OpenSim in your own research Become confident in your data workflow Achieve your project goals and share your results Advance your research!

The Workshop Software OpenSim 3.2

Getting the most out of the workshop: Set clear and manageable project goals Help each other Use your resources: lectures and online materials Still need help? Find the right person to ask your questions Have fun and take breaks

How we hope you will respond: Continue to use OpenSim in your research Develop musculoskeletal models and contribute them to the biomechanics community Use OpenSim in your teaching and contribute new teaching materials Add features to the software and share with others Complete our survey so we can improve later workshops