Exercise for rotator cuff tendinopathy: proposed mechanisms of recovery

Key points

1. 01Resisted exercise is the first-line recommended treatment for rotator cuff tendinopathy, but non-response rates remain unacceptably high
2. 02Four proposed recovery mechanisms are: tendon structural changes, neuromuscular improvements, psychosocial factor modification, and normalization of pain and sensorimotor processing
3. 0340-50% of patients develop recurrent chronic symptoms, suggesting current exercise-only approaches are insufficient for many
4. 04Psychological factors such as pain catastrophizing, self-efficacy, and treatment expectations predict patient-reported outcomes and should be monitored throughout rehabilitation
5. 05Patient subgrouping based on mechanistic biomarkers may enable matched and stepped care to improve outcomes for non-responders

How it was conducted

Design

Narrative review with a proposed theoretical model

Scope

Resistance exercise mechanisms in rotator cuff tendinopathy across four domains: tendon structure, neuromuscular, psychosocial, and pain/sensorimotor processing

Evidence base

Mostly levels IV and V evidence (case series, mechanistic reasoning); some systematic reviews from lower extremity tendinopathy used to extrapolate hypotheses

Primary aim

Propose a mechanistic framework linking exercise to patient outcomes to guide subgroup development and patient-specific treatment

What they found

• In a cohort study of 23 participants, pre-post exercise showed a small or no effect on morphological tendon thickness
• One study found that after a resisted exercise intervention, peak spatial frequency radius values (a measure of collagen organization) increased in patients with RC tendinopathy to match healthy control values
• A causal mediation analysis found that changes in scapular motion did not mediate improvements in pain or disability with resisted exercise
• One study evaluating exercise and manual therapy over 2 weeks found that baseline differences in local and remote pressure and heat pain thresholds between shoulder pain patients and controls were normalized after intervention
• In a small pilot study, improvement in patient-reported outcomes was related to increased rate of force development during resisted isometric external rotation
• Higher levels of emotional distress and kinesiophobia were associated with greater disability over one year in patients with shoulder pain

Limitations

• Evidence for proposed mechanisms in rotator cuff tendinopathy is predominantly levels IV and V (case series, mechanistic reasoning), with few high-quality RCTs examining mechanism change
• Most mechanistic hypotheses are extrapolated from lower extremity tendinopathy research, which may not directly apply to the rotator cuff
• No studies have evaluated the direct effects of exercise alone on central pain-processing measures or cortical excitability in rotator cuff tendinopathy
• Methodological inconsistency across studies (different tasks, outcome measures, participant characteristics) limits synthesis and comparison of neuromuscular findings

Why it matters

For patients

People with persistent shoulder pain from rotator cuff tendinopathy may benefit from understanding that exercise affects multiple body systems, not just tendon tissue, and that addressing psychological factors and pain sensitivity alongside standard exercise may improve outcomes.

For clinicians

This framework encourages assessment of tendon structure, neuromuscular performance, psychosocial factors, and central pain processing in patients with rotator cuff tendinopathy, to inform patient-specific and stepped-care exercise prescriptions for non-responders.

For readers

This review offers a theoretical but evidence-anchored model for why exercise works in rotator cuff tendinopathy, and points to the need for mechanistic trials that test subgroup-matched treatment strategies.