Individualized systems-informed corrective exercise for adults meeting prespecified criteria for upper crossed syndrome: protocol for a randomized controlled trial

Background: Heterogeneity in eligibility criteria, intervention content, and exercise-progression rules has limited the reproducibility of research on upper crossed syndrome. This trial will examine the added effect of a structured, individualized, staged corrective-exercise program on adults who meet prespecified criteria for this phenotype. Methods: In this parallel randomized controlled trial, 36 women and men aged 18–40 years with forward head and shoulder posture and increased thoracic kyphosis will be allocated 1:1, stratified by sex. Over 12 weeks, both groups will attend three sessions per week and receive stationary cycling, indication-based stretching and mobilization, and education on healthy movement habits. The intervention group will additionally receive a systems-informed program encompassing restoration of range of motion, muscle-activation retraining, correction of movement patterns, progressive load tolerance, and preparation for health-enhancing physical activity. The primary outcome is the baseline-adjusted week-12 between-group difference in a multivariate profile comprising the forward-head, forward-shoulder, and thoracic-kyphosis angles. Scapular-muscle electromyography, range of motion, and balance are secondary outcomes. The primary exploratory electroencephalographic outcome is change in central relative alpha power during quiet standing with eyes open. Posture, range of motion, and balance will be assessed at baseline, week 12, and four-week follow-up; electromyography and electroencephalography at baseline and week 12. The primary analysis will use MANCOVA adjusted for baseline and sex, with Pillai's trace; longitudinal analyses will use linear mixed models. Effect estimates and 95% confidence intervals will be reported. Conclusions: This study will test the added effect of a reproducible corrective-exercise framework beyond the shared active-control components. The four-week follow-up will not support inference about long-term prevention of recurrence. Ethics and trial registration: Ethics approval: IR.UI.REC.1404.053. Trial registration: IRCT20250921067305N1.