Ear buds may have sensors to gather orientation information such as accelerometer measurements during user movements. A host electronic device may communicate wirelessly with the ear buds and may form part of an ear bud system that supplies the user with coaching and feedback while evaluating user performance of a head movement routine or other exercise routine. During operation, the ear buds may gather accelerometer data in a first reference frame such as a reference frame associated with the ear buds and may use a rotation matrix to rotate the data in the first reference frame into a second reference frame such as a neutral reference frame with a fixed orientation to the earth. The data in the neutral reference frame may be analyzed using a user head pose look-up table to categorize measured user head positions as corresponding to respective user head poses.