Hip Joint Centre Calculation

[Logan Wade]

Dear Scott and Antoine,

I was just wondering if you might be able to provide some more information on how you calculated hip joint centres in your recent OpenCap publication. Apologies if this has already been asked, I could not find it in the forum. We are looking to do a similar analysis as your publication, thus we want to replicate the same scaling between both OpenCap and our motion capture data. However, i cannot really find any information for how this was done. I have followed your citations to Rajagopal (https://ieeexplore.ieee.org/document/7505900) who then cited Gamage (https://www.sciencedirect.com/science/a ... 9001001609). Did you calculate this hip joint centre using Gamage's formula in python, or was this done in by your motion capture system software?

Any advice or links you could share on how to implement this calculation of hip joint centres would be greatly appreciated.

Kind regards,

Logan Wade

[Logan Wade]

Also, to calculate this hip joint centre, did you perform a functional trial, or did you just use a squatting trial to do this? I have downloaded your dataset but could not see a function hip trial, only DJ, STS, walking, squats and a static file?

[Scott Uhlrich]

With the mocap data, we computed a functional hip joint center using the method described in Piazza 2004. https://pubmed.ncbi.nlm.nih.gov/14757454/

We didn't do functional hip joint centers for the opencap model. All scaling was based on the augmented markers in a standing neutral trial.

[Logan Wade]

Thanks Scott. Much appreciated