The influence of exercise therapy dosing on pain and functional outcomes in patients with subacromial pain syndrome: A systematic review*

Background: The objective was to identify exercise therapy dosing parameters for subacromial pain syndrome (SAPS) associated with improved pain and function outcomes (via effect sizes) and determine the extent of exercise intervention reproducibility. Methods: An electronic search of PubMed/MEDLINE, Cumulative Index to Nursing and Allied Health Literature, EMBASE, Cochrane Database of Systematic Reviews, and SportDiscus identified studies that used exercise therapy exclusively to treat SAPS. Exercise therapy dosing parameters were extracted and within-group effect sizes were calculated for all pain and functional outcomes. Template for Intervention Description and Replication and Consensus on Exercise Reporting were used to record intervention reporting. The risk of bias and Grading of Recommendations, Assessment, Development, and Evaluation were assessed by two reviewers. Results: Twenty-one trials with 674 subjects were included. Effect sizes for pain and function were large in 18 studies, medium in six studies, and small or no effect in four studies, despite the type of supervision. With moderate certainty, effect sizes of pain and function were not influenced by exercise therapy dosing parameters. Intervention reporting was generally poor. Discussion: Exercise therapy for SAPS was associated with large effect sizes for improvement in pain and function but optimal exercise therapy dosing parameters could not be identified. Strong recommendations conditionally suggest treating SAPS with a variety of exercise therapy dosing parameters.