A device provides a quick, easy and accurate method to measure a persons trunk rotation in a seated position. This measurement may be vital to identify, evaluate, and treat chronic low back pain (LBP) or to improve sports performance that requires trunk rotation, such as golf. The device may include a measuring arch, a bracket, a main arm, and a pole. The device may be attached to a seat, stool, chair, or the like, or the device may include a seat. To use, a subject may sit on the seat with arms out to the side. The subject may then rotate and move the pole, which may be oriented vertically, with her arm around the measuring arch.
