From the ISB standard (Wu et al, 2005)

"The standardization of motions is only described for right shoulder joints. Whenever left shoulders are measured, it is recommended to mirror the raw position
data with respect to the sagittal plane (z = -z). Then, all definitions for right shoulders are applicable."

This should work for your application.

- Andy

Quote Originally Posted by ShayneVial View Post
Good day,

I am relatively new to motion analysis and how to interpret joint angles.

I have collected 3D motion data of the shoulder, elbow, and wrist joints on elite badminton athletes performing the short serve. I have subjects that are left and right handed, I would like to compare individuals however I am getting different joint angles for left and right handed subjects (for obvious reasons).

For example, around the X axis there is no issue, flexion about the shoulder joint is positive. However, with regards to shoulder abduction/adduction & internal/external rotation, I am unsure of how to interpret the data as it is not as simple as making left handed subjects negative while leaving right handed subjects as positive (to make a comparison).

I hope I have explained the issue correctly!