TY - JOUR AU - Kamonseki, Danilo Harudy AB - Introduction Shoulder pain is a debilitating musculoskeletal condition with functional, physical, and psychological impacts. Interventions for chronic shoulder pain should address the biopsychosocial model, with Cognitive Functional Therapy (CFT) emerging as a promising physiotherapy approach. CFT approaches the multidimensional nature of pain, integrating physical and cognitive aspects. To date, no study has assessed the effectiveness of CFT in individuals with chronic shoulder pain. Therefore, this randomized controlled trial aims to compare the effects of CFT to therapeutic exercises on pain intensity, disability, self-efficacy, sleep quality, biopsychosocial aspects, and central pain processing in individuals with chronic shoulder pain. Methods This will be a randomized controlled trial, single-blinded with two parallel groups. Seventy-two individuals with chronic shoulder pain will be randomly assigned to one of two groups: CFT or Therapeutic exercise. The interventions will last 8 weeks, with the CFT group receiving therapy once a week and the therapeutic exercise group receiving sessions twice a week. The primary outcomes will be pain intensity and disability, while the secondary outcomes will include function, self-efficacy, sleep quality, biopsychosocial factors, perception of improvement/deterioration, and central pain processing. The outcome measures will be assessed at baseline, 4th week, end of treatment (8th week), and 12th-week follow-up. Conclusion The results of this study will contribute to understanding the effectiveness of CFT in treating individuals with chronic shoulder pain. Trial registration number: NCT06542666 Introduction Chronic shoulder pain has an estimated annual prevalence ranging from 0.7% to 55.2% in the general population [1]. It affects 45% of individuals engaged in repetitive work-related movements [2], pointing to an annual incidence of 37.8 per thousand people. Shoulder pain has significant physical, social, and psychological impact, often contributing to work limitations and difficulties in daily activities. This results in a significant economic burden on society due to the use of medication, sick leave, medical, and hospital expenses [3]. Furthermore, approximately 50% of individuals with shoulder pain continue to experience persistent pain after one year [4], indicating a high likelihood of chronification. The condition is also linked to functional impairment and psycho-emotional distress, including depression, anxiety, decreased quality of life, kinesiophobia, catastrophizing, and low self-efficacy [3,5,6]. Thus, chronic shoulder pain presents multifactorial characteristics connecting the painful experience to fear-avoidance behaviors, which can further reduce function [6,7]. Therefore, interventions for individuals with chronic shoulder pain should align with the biopsychosocial model [8,9]. Therapeutic exercises are the primary recommendation for the treatment of shoulder pain [10–12]. These exercises typically focus on joint mobility, muscle stretching, and strengthening, often targeting the scapulothoracic and glenohumeral muscles [10,13,14]. However, given the strong association between psychosocial factors and the prognosis of chronic shoulder pain [5,15], exercise therapy alone may not adequately address the multidimensional nature of pain, as it fails to target the psychosocial aspects. This emphasizes the need for interventions that encompass physical, emotional, and behavioral components to yield more relevant and effective outcomes [16]. Cognitive Functional Therapy (CFT) is a patient-centered, individualized approach to address physical, psychological, emotional, and lifestyle barriers to improve pain symptoms, disability, and maladaptive cognitive-behavioral factors [17,18]. The CFT is structured into three phases: (1) making sense of pain, (2) exposure with control, and (3) lifestyle changes [19–21], including an approach for improving physical activity and sleep quality. Sleep has an important role in modulating physical and psychological health. Disruptions to sleep have been shown to significantly diminish quality of life and exacerbate the experience of pain in individuals with musculoskeletal conditions [22,23]. By contrast, physical activity has been identified as a key factor in promoting health, diminishing pain, and improving sleep quality, thereby influencing recovery and pain management outcomes [22,23]. Previous studies have demonstrated the positive effects of CFT on pain intensity, disability, and psychological factors in individuals with chronic low back pain [20,24–27], neck pain [28,29], and knee osteoarthritis [30]. Although CFT has shown significant and positive results for the treatment of chronic pain in other musculoskeletal conditions, randomized controlled trials investigating the application of CFT to treat chronic shoulder pain have not yet been conducted. Therefore, this study aims to compare the effects of CFT with therapeutic exercise on biological aspects of pain (pain intensity, disability, function, perception of improvement/deterioration, and central pain processing), and psychosocial aspects of pain (sleep quality, self-efficacy, and biopsychosocial factors). We hypothesize that CFT will lead to greater improvements in these outcomes compared to therapeutic exercise. Methods Study design This study is a randomized controlled trial with a superiority design, single-blinded with two parallel groups. Outcome assessors will be blinded to participants’ assigned treatment groups. This protocol follows the Standard Protocol Items: Recommendations for Interventional Trials (SPIRIT) statement and checklist [31]. This study was prospectively registered at clinicaltrials.gov (NCT06542666) and The World Health Organization data set is described in Table 1. The authors confirm that all ongoing and related trials for this intervention are registered. Download: PPT PowerPoint slide PNG larger image TIFF original image Table 1. World Health Organization trial registration data set. https://doi.org/10.1371/journal.pone.0320025.t001 Research site The evaluation and intervention procedures of this study will be conducted at the Laboratory for the Study of Balance, Dynamometry, and Electromyography and at the Physiotherapy School Clinic of the Universidade Federal da Paraíba, Brazil, in 2025. Sample The study will include adults aged between 18 and 60 who report shoulder pain lasting at least 3 months. They should rate their shoulder pain 4 or higher on the 11-point Numerical Pain Rating Scale (NPRS) over the past week [32], and high level of disability (Shoulder Pain and Disability Index score ≥ 47) [33,34] or moderate irritability according to Staged Approach for Rehabilitation Classification: Shoulder Disorders (STAR–Shoulder) [35,36]. Non-inclusion criteria will be apply to individuals with: a history of fracture or surgery of the clavicle, scapula and/or humerus; surgical stabilization or repair of the rotator cuff; a history of dislocation, instability (positive Groove Sign or Seizure Test) and/or rotator cuff rupture (positive Arm Drop Test); adhesive capsulitis verified by the presence of pain with gradual onset associated with stiffness and reduced passive and active mobility; reproduction of pain in the shoulder that radiates to the entire upper limb, ongoing pregnancy; tingling or numbness in the upper limb or any other symptom in the upper limb during tests on the thoracic or cervical spine (Positive Spurling Test); systemic disease or neurological condition that can alter muscle strength and sensitivity, such as fibromyalgia, rheumatoid arthritis, gout, lupus, diabetes and/or stroke; physiotherapy treatment for shoulder pain in the previous 3 months, corticosteroid injection in the shoulder region in the last 3 months, and active treatment for cancer [37–39], impairments in sensation, blood clotting disorders, and/or contraindications to the application of ice. Individuals with surgeries, fractures, musculoskeletal or neurological conditions preventing them from accessing treatment, or those who received corticosteroid injections in the shoulder region during the treatment or follow-up period will be discontinued from the study. The sample size was calculated using the SampSize App (https://app.sampsize.org.uk/) and the following formula described by Flight et al (2015) [40]: The calculation was based on an estimated mean difference of 18 points [41] (standard deviation of 24.6) [42] in shoulder disability, assessed with Shoulder Pain and Disability Index (SPADI), with a two-tailed significance set at 0.05, power at 80%, and accounting for a 15% dropout, which resulted in 36 individuals per group for a total of 72 individuals. The sample size, calculated based on pain intensity (a mean difference of 2 points and a standard deviation of 2.5 on the NPRS), resulted in a total sample of 48 individuals. Therefore, the sample size calculation for this study was based on shoulder disability. Recruitment The recruitment of the individuals will be carried out between February 2025 and June 2026. Participants will be recruited through flyers posted in university buildings, orthopedic and rheumatology clinics, public places, and community health clinics in João Pessoa. Recruitment strategies will also include online advertisements (e.g., social media) and the personal and professional networks of the researchers involved in the study. Randomization Participants will be randomly assigned (1:1 ratio) to the CFT or Therapeutic Exercises groups (Fig 1). An independent researcher will carry out the randomization using a computer-generated sequence from http://www.randomization.com, stratified by age (