One-year effectiveness of high-load compared with low-load strengthening exercise on self-reported function in patients with hypermobile shoulders: a secondary analysis from a randomised controlled trial.

Objectives: To investigate the long-term effectiveness of high-load versus low-load strengthening exercise on self-reported function in patients with hypermobility spectrum disorder (HSD) and shoulder symptoms.

Methods: A secondary analysis of a superiority, parallel-group, randomised trial (balanced block randomisation 1:1, electronic concealment) including adult patients (n=100) from primary care with HSD and shoulder pain and/or instability ≥3 months. Patients received 16 weeks of shoulder exercises (three sessions/week): HEAVY (n=50, full-range, high-load, supervised twice/week) or LIGHT (n=50, neutral/mid-range, low-load, supervised three times in total). The 1-year between-group difference in change in self-reported function was measured using the Western Ontario Shoulder Instability Index (WOSI, scale 0-2100, 0=best). Secondary outcomes were self-reported measures including changes in shoulder-related symptoms, function, emotions and lifestyle, quality of life, patient-perceived effect, treatment utility and adverse events. A blinded analyst conducted the analyses using linear mixed model repeated measurements analysis.

Results: One-year data were available in 86 out of 100 participants (79% women, mean age 37.8 years) (LIGHT 84%, HEAVY 88%). The mean WOSI score between-group difference favoured HEAVY (-92.9, 95% CI -257.4 to 71.5, p=0.268) but was not statistically significant. The secondary outcomes were mostly inconclusive, but patients in HEAVY had larger improvement in the WOSI emotions subdomain (-36.3; 95% CI -65.4 to -7.3, p=0.014). Patient-perceived effect favoured HEAVY anchored in WOSI-emotions (55% vs 31%, p=0.027) and WOSI-lifestyle (50% vs 29%, p=0.042).

Conclusion: High-load shoulder strengthening exercise was not superior to low-load strengthening exercise in improving self-reported function at 1 year. High-load strengthening exercise may be more effective in improving patient emotions about shoulder pain and function, but more robust data are needed to support these findings.

Trial Registration Number: NCT03869307.