Does Altering Sitting Posture Have a Direct Effect on Clinical Shoulder Tests in Individuals With Shoulder Pain and Rotator Cuff Degenerative Tears?

Abstract

Posture variations have been repeatedly linked to shoulder kinematics, strength, range of motion, and rotator cuff diseases. However, to our knowledge, no study has yet examined their possible link with shoulder pain provocation and pain levels during clinical shoulder tests. The objective was to examine whether changing posture while sitting modifies pain provocation and pain level during performance of 3 clinical shoulder tests in participants with shoulder pain and rotator cuff degenerative tears (RCDTs). Seventy individuals were allocated into 2 groups by an experienced physical therapist: 35 participants with symptomatic shoulders and RCDT diagnosed by ultrasound (tear size = 1.0 +/- 0.5 cm) and 35 control participants with no symptoms in the upper limb. All participants were tested by a second physical therapist for pain provocation (yes/no) and pain level (visual analog scale) using 3 common clinical shoulder tests: the Neer, the Hawkins-Kennedy, and the empty can while sitting in a neutral, slouched, and upright posture. Shoulder muscle forces were examined by a hand-held dynamometer for possible correlations only in the neutral posture. All participants were asked to fill out the quick DASH (disabilities of the arm shoulder and hand) questionnaire. In the symptomatic group, all 3 clinical tests demonstrated similar pain provocation (100% repeatability) and pain level in all 3 sitting postures (visual analog scale scores 3.7-4.4). Muscle force mean ranges of the study groups were 4.4 to 7 kg and, in the control group, 6 to 10.5 kg. No correlations were found between age, body mass index, shoulder pain, hand dominance, onset of symptoms, severity, and tear size with any of the dependent variables. Changing posture while sitting did not directly affect pain provocation and pain levels during performance of 3 clinical shoulder tests in participants with shoulder pain and RCDTs.