Robotic arm revolute joints speeds

Hi, I currently have a robotic arm in the Isaac-sim environment and I would like to continuously get its joints’ revolute speeds. I tried to use the get_joint_velocities() method on the SingleManipulator entity (that is my robotic arm in simulation) as found from omni.isaac.core API, and while I am getting values for each joint, I don’t think they are the revolute speeds and here’s why I think so:
I moved only the base joint of the robotic arm in simulation in an ocsillatory motion and the robot sucessfully performs the oscillatory motion but here’s my observation for the speed values:
1- All the joints have non-zero speeds, while I was expecting the speeds to be all zeroes or close to zero except for the base joint’s
2- Despite the change of rotation’s direction dictated by the oscillations, the speed values barely change during the robot’s motion, while i expect a speed variation with a change of signs given the rotation direction reversal from time to time.

Any guidance to solve these ambiguities would be appreciated. Thanks!