Shoulder angles provided using Noraxon IMU systems are descibed in the video below..
NOTE: The video explains that the initial position of the Shoulder Rotation Ext angle is at -45 degrees, which reflects the shoulder being internally rotated by 45 degrees with the palms facing the sides. This only applies to MR3 software versions.
In versions of myoRESEARCH MR 4.0 and newer, an upper arm correction is applied that affects the initial expected Shoulder Rotation Ext angle position in the standing calibration pose. We detect the person-specific elbow flexion axis position based on hinge assumptions for the elbow joing. This means that the Standing Pose Shoulder Rotation Ext value is different for very recording and doesn’t following the Shoulder Rotation Ext = -45 deg assumption.
For more details about assumptions made to the body position in the intial Standing Pose calibration, visit the 🔗IMU Calibration Guide.
