Combined Respiratory Muscle Training Improves Pulmonary Function in Upper Thoracic Spinal Cord Injury: A Randomized Trial

Abstract Background: Upper thoracic spinal cord injury (SCI) patients face significant respiratory impairments, increasing morbidity and mortality risks. This study evaluates the efficacy of combined respiratory muscle training (RMT) compared to single-modal training in improving pulmonary function. Methods: A randomized controlled trial enrolled 20 patients (aged 25–45 years) with complete upper thoracic SCI (T1–T4). Participants were randomly assigned to combined RMT (diaphragmatic breathing, incentive spirometry, active cycle of breathing techniques, and inspiratory muscle training) or single-modal RMT (incentive spirometry alone) for 5 weeks. Primary outcomes included chest expansion (nipple, axillary, xiphisternum levels) and pulmonary function (incentive spirometry, peak flow meter). Data were analyzed using paired t-tests. Results: Combined RMT significantly improved chest expansion (nipple: +0.98 cm, p=0.03; axillary: +1.05 cm, p=0.04; xiphisternum: +0.88 cm, p=0.03) and pulmonary function (incentive spirometry: +3.37 L, p=0.05; peak flow: +203.89 L/min, p=0.05) compared to single-modal RMT. No adverse events were reported. Conclusions: Combined RMT is more effective than single-modal RMT in enhancing pulmonary function in upper thoracic SCI patients, suggesting its potential to reduce pulmonary complications. Keywords: spinal cord injury, respiratory muscle training, pulmonary function, upper thoracic, rehabilitation