International Society of Biomechanics
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An Open Invitation to the Musculoskeletal Modeling Research Community

On behalf of my collaborators and the organizers of the 2010 ASME Summer Bioengineering Conference, I would like to invite you to participate in a "Grand Challenge Competition to Predict In Vivo Knee Loads" to be held at the upcoming conference June 16-20 in Naples, Florida (

The goal of the competition is to quantitatively evaluate model-based estimates of muscle and contact forces in the knee during gait using in vivo tibial contact force data collected from a subject with an instrumented knee implant. Competitors will use any musculoskeletal (or other) modeling software and methods they desire to estimate medial and lateral tibial contact forces for two specified gait trials WITHOUT knowing the actual contact force measurements. Data files containing predicted medial and lateral contact forces will be submitted with each competition abstract. Abstracts will be judged using standard ASME Summer Bioengineering Conference criteria along with two additional criteria: Accuracy and Novelty. The in vivo contact force measurements will be released after the abstract submission deadline, and the highest scoring abstracts will be presented in a special session at the conference. The winner of the competition will be announced in an award and "post-mortem" session where lessons learned from the competition will be discussed by all competitors.

Dr. Thor Besier and I have created a project ( to provide all necessary information about the competition and experimental data available for it. Competition data have already been posted by Dr. Darryl D'Lima at the Shiley Center for Orthopaedic Research and Education at Scripps Clinic. All data collection and distribution have been IRB approved. Some in vivo contact force data are included with the data sets to assist competitors in developing their musculoskeletal models. Release of the implant geometry (laser scans) and an OpenSim leg model of the subject (including contact models of the implant components) are planned for the near future.

If you would like to stay informed about the competition, please sign up for the "kneeloads-news" mailing list on the competition's project (under Advanced->Mailing Lists). You will automatically be asked to join this mailing list any time you download data or documents for the competition (under Downloads). If you encounter any problems with the data, or if you have any questions, we will be using the Public Forum feature of (under Advanced ->Public Forums->open-discussion) as a central location for researchers to post their inquiries and for the research team to respond.

We look forward to having researchers around the world take our challenge to see how well they can predict in vivo knee loads during gait.


B.J. Fregly, Ph.D., University of Florida

Research team:

B.J. Fregly, Ph.D., University of Florida
Darryl D'Lima, M.D., Ph.D., Shiley Center at Scripps Clinic
Thor Besier, Ph.D., Stanford University
David Lloyd, Ph.D., University of Western Australia
Marcus Pandy, Ph.D., University of Melbourne