Marker set for back sagittal movements

[Tomer Yona]

Hey everyone,

I want to collect the flexion/extension movements of the back using a qualysis system.

I found some marker set in precious studies, all used vertebrae counting as placement for their markers.
As I'm unsure how accurate is it, I wondered if using C7 as my prominent location and than just place a marker every 5 cm (or another distant) might be more accurate?

Any thoughts?


Thanks!

[Edmund Cramp]

My experience with this sort of question about 40 years ago in the gait analysis environment is that there are two potential causes for 3D measurement errors. These are normally only "Was the location detected accurately?" or "Was the marker placed accurately?"
So all you need to do is start by performing a few simple data collection verification's, for example placing the markers on a metal or plastic object that could be worn on the subject. Then just measure the locations and relationships and then walk through the data collection volume holding the object and recording the data, so that you can verify that the measured relationships are correct. Then attach the marker collection object to your back and walk through the data collection to check everything again. All this can be done personally - once you are confident about your data collection then all you have to do is make sure that you are placing the markers accurately on the subject.