I'm curious about RRA

[Soyoung Joo]

Hello

I have a question

1. Are filtering and RRA different concepts?

2. When I acquire data from QTM, convert the file to C3D, and then check the data in Open Sim, I wonder why RRA is needed.

1-1) If you read the data from OpenSim with the marker and force filtering completed in the visual 3D software, the filtering for the marker or force has already been applied, so it is questionable whether RRA needs to be reapplied.

1-2) If the path in 1-1 is not normal, do you follow the order of reading data from the QTM -> C3D (no filtering) -> mot, trc conversion open SIM software and apply RRA?

[Ross Miller]

Hi Soyoung,

I would not equate RRA with filtering. There will be non-zero residuals in an inverse dynamics analysis even in a hypothetical situation where the skeletal motion and external forces are measured with perfect accuracy.

I recommend the following paper, where the first few paragraphs describe the issue well:

https://doi.org/10.1016/S0021-9290(01)00158-0

Ross

[Soyoung Joo]

Hi Soyoung,

I would not equate RRA with filtering. There will be non-zero residuals in an inverse dynamics analysis even in a hypothetical situation where the skeletal motion and external forces are measured with perfect accuracy.

I recommend the following paper, where the first few paragraphs describe the issue well:

https://doi.org/10.1016/S0021-9290(01)00158-0

Ross

Hi Ross Miller,
Thanks for the reply, it was helpful!