Contents lists available at ScienceDirect Musculoskeletal Science and Practice journal homepage: www.elsevier.com/locate/msksp Original article Does pectoralis minor stretching provide additional beneft over an exercise program in participants with subacromial pain syndrome? A randomized controlled trial Héctor Gutiérrez-Espinoza a,b , Felipe Araya-Quintanilla a,c , Rodrigo Gutiérrez-Monclus d , Mario Ríos-Riquelme e , Celia Álvarez-Bueno f,g,∗ , Vicente Martínez-Vizcaino f,h , Iván Cavero-Redondo f,g a Faculty of Health, Universidad de las Américas, Santiago, Chile b Physical Therapy Department, Clinical Hospital San Borja Arriarán, Santiago, Chile c Faculty of Health, Universidad SEK, Santiago, Chile d Orthopedic Surgeon, Instituto Traumatológico, Santiago, Chile e Department Sciences in Physical Activity, Universidad de Santiago, Santiago, Chile f Universidad de Castilla-La Mancha, Health and Social Research Center, Cuenca, Spain g Universidad Politécnica y Artística del Paraguay, Asunción, Paraguay h Facultad de Ciencias de la Salud, Universidad Autónoma de Chile, Talca, Chile ARTICLE INFO Keywords: Subacromial pain syndrome Muscle stretching exercises Exercise therapy Randomized clinical trial ABSTRACT Background: Adaptive shortening of the pectoralis minor is one of the biomechanical mechanisms associated with subacromial pain syndrome (SPS). Objective: To compare the efects of an exercise program alone with an exercise program in combination with pectoralis minor stretching in participants with SPS. Design: Randomized controlled trial. Methods: Eighty adult participants with SPS were randomly allocated to two groups. The control group (n = 40) received a 12-week specifc exercise program and the intervention group (n = 40) received the same program plus stretching exercises of the pectoralis minor muscle. The primary outcome measure was shoulder function assessed by a Constant−Murley questionnaire, and the secondary outcomes were the Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaire, visual analog scale (VAS), and pectoralis minor resting length. Results: The present study shows no diference between the two interventions according to the Constant−Murley questionnaire (1.5 points; p = 0.58), VAS at rest (0.2 cm; p = 0.11), VAS at movement (0.5 cm; p = 0.08), and pectoralis minor resting length (0.3 cm; p = 0.06). The DASH questionnaire showed greater functional improvement in the control group (5.4 points; p = 0.02). Finally, only pectoralis minor length index showed diference statistical signifcant in favor of intervention group (0.3%; p = 0.04). Conclusion: In the short-term, the addition of a program of stretching exercises of the pectoralis minor does not provide signifcant clinical beneft with respect to functional improvement or pain reduction in participants with SPS. Trial registration: Brazilian registry of clinical trials UTN number U1111-1210-3555. Registered 5 March 2018. 1. Introduction Subacromial pain syndrome (SPS) is the most prevalent disorder causing pain and dysfunction of the shoulder, accounting for 50–86% of all shoulder-related visits to primary care centers (Van der Windt et al., 1995; Ostör et al., 2005) and 36% of visits to secondary care centers (Juel and Natvig, 2014). In 1972, Neer proposed the concept and di- agnosis of ‘‘impingement syndrome’’ based on a series of cases, and advocated anterior acromioplasty (Neer, 1972); this label was based on the mechanism of structural impingement of the subacromial space. https://doi.org/10.1016/j.msksp.2019.102052 Received 9 April 2019; Received in revised form 18 August 2019; Accepted 22 August 2019 ∗ Corresponding author. Universidad de Castilla-La Mancha, Edifcio Melchor Cano, Centro de Estudios Sociosanitarios, Santa Teresa Jornet s/n, 16071, Cuenca, Spain. E-mail address: celia.alvarezbueno@uclm.es (C. Álvarez-Bueno). Musculoskeletal Science and Practice 44 (2019) 102052 2468-7812/ © 2019 Elsevier Ltd. All rights reserved. T