Shoulder functional assessments in persons with chronic neck/shoulder pain and healthy subjects: Reliability and effects of movement repetition

Abstract

Obtaining reliable functional capacity measures from injured workers is an essential part of the return to work (RTW) process. The present study compares shoulder functional outcomes between healthy individuals and others with neck/shoulder pain, assesses reliability and examines the influence of repetitive movements on shoulder function. Subjects performed trials of flexion and abduction active range of motion (ROM), and cumulative power output (PO) in a pushing/pulling task on the Baltimore Therapeutic Equipment Simulator II in two consecutive sessions. Tasks were assessed before and after performing a repetitive arm task, during which heart rate (HR) was recorded, until scoring 8 on the Borg CR-10 scale or on a 11-point numeric rating scale (NRS) for pain. Persons with chronic neck/shoulder pain (intensity ≥ 3/10 for > 3 months) (n = 16) and an age- and sex-matched control group (n = 16). Functional shoulder measures demonstrated strong inter-session reliability, except PO in the pain group. Average repetitive task duration was shorter in the pain group (4 min vs. 7 min). The protocol detected both pain- and time-related impairments, with HR and PO being sensitive to movement duration and ROM to pain.