Isometric versus isotonic exercise in individuals with rotator cuff tendinopathy-Effects on shoulder pain, functioning, muscle strength, and electromyographic activity: A protocol for randomized clinical trial

• Published in: PloS one 2023-11, Vol.18 (11), p.e0293457-e0293457
• Main Authors: Rodrigues da Silva Barros, Bianca, Dal'Ava Augusto, Denise, de Medeiros Neto, João Felipe, Michener, Lori Ann, Silva, Rodrigo Scattone, Sousa, Catarina de Oliveira
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Biology and Life Sciences; Clinical trials; Consent; Electromyography; Exercise Therapy - methods; Group dynamics; Humans; Intervention; Isometric exercise; Medicine and Health Sciences; Middle Aged; Muscle contraction; Muscle strength; Muscle Strength - physiology; Muscles; Pain; Patient compliance; Physical fitness; Physical Sciences; Physical therapy; Randomized Controlled Trials as Topic; Rotator cuff; Rotator Cuff - physiology; Shoulder; Shoulder - physiology; Shoulder pain; Shoulder Pain - therapy; Strength training; Study Protocol; Tendinopathy - therapy; Ultrasonic imaging; Young Adult
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0293457

Rotator cuff tendinopathy is a common shoulder disorder in which the primary treatment is resistance exercises. Isometric exercises are being studied for lower limb tendinopathies but not for rotator cuff tendinopathy. This protocol for a randomized clinical trial aims to compare the effects of two types of exercise (isometric and isotonic) on shoulder pain, functioning, muscle strength, and electromyographic activity in individuals with rotator cuff tendinopathy. Forty-six individuals (18 to 60 years old) with shoulder pain for more than three months and unilateral supraspinatus and/or infraspinatus tendinopathy will participate in this trial. Individuals will be randomized into two exercise groups: isometric or isotonic. The following outcomes will be evaluated before and after the first session and after six weeks of intervention: shoulder pain and functioning; isometric strength of shoulder elevation and lateral and medial rotation; and electromyographic activity of medial deltoid, infraspinatus, serratus anterior, and lower trapezius. Groups will perform stretching and strengthening of periscapular muscles. The isometric group will perform three sets of 32 s, at 70% of maximal isometric strength. The isotonic group will perform concentric and eccentric exercises (2 s for each phase) in three sets of eight repetitions at a load of eight repetition maximum. The total time under tension of 96 s will be equal for both groups, and load will be adjusted in weeks three and five of the protocol. Treatment effect between groups will be analyzed using linear mixed model. Trial registration number: Universal Trial Number (UTN) code U1111-1284-7528 and Brazilian Clinical Trials Registry platform-RBR-3pvdvfk.