Active shoulder flexion in sitting is sometimes accompanied by thoracolumbar extension, along with cervical side-flexion and rotation, which may result in inconsistent documentation of shoulder range motion values. The purposes of this study are to examine intra-rater and inter-rater reliability of a method for measuring active shoulder flexion range of motion in the sitting position, and to determine if different lumbar spine positions will result in a change in subjects’ active shoulder flexion range of motion in sitting.