Rehabilitation of neck-shoulder pain in women industrial workers: A randomized trial comparing isometric shoulder endurance training with isometric shoulder strength training

Objectives: To study whether isometric shoulder endurance was more advantageous than isometric shoulder strength training in reducing pain and perceived exertion and to increase shoulder function through improved muscle endurance and strength. Design: Randomized trial. Setting: Three occupational health care centers. Participants: Women industrial workers with nonspecific neck-shoulder pain. The International Classification of Diseases, 10th Revision (ICD-10) diagnosis was "cervicobrachial syndrome" (M53.1). Thirty-eight patients completed the isometric shoulder endurance training and 31 patients completed the isometric shoulder strength training. Intervention: Twelve weeks of training. Main Outcome Measures: Self-reported pain and rating of perceived exertion (RPE), arm motion performance test, shoulder muscle strength, shoulder muscle endurance, and shoulder functional tests, as well as follow-up after supervised training had ended. Results: The isometric shoulder strength training resulted in an almost one-scale step decrease in RPE at work and a 5% to 15% improvement of arm motion performance compared with the endurance training. The isometric shoulder strength training more effectively improved left side shoulder abduction strength (p < .026), but no major differences were found for the other strength measurements. The isometric shoulder endurance training was not more successful than the strength training in the endurance test (p .51 to .81). Conclusions: Physical training programs for neck-shoulder pain may include isometric shoulder muscular strength exercise in addition to isometric shoulder endurance training, rather than endurance training only.