Effects of combined inspiratory and expiratory muscle training in pediatric kidney transplant recipients: a randomized controlled study

Background: Children with chronic kidney disease may continue to experience respiratory muscle weakness and reduced functional capacity after kidney transplantation. While inspiratory muscle training (IMT) improves respiratory muscle strength, evidence on the combined use of IMT and expiratory muscle training (EMT) is limited. This study investigated whether an 8-week combined IMT + EMT program integrated with chest physiotherapy improves pulmonary function, respiratory and peripheral muscle strength, and functional capacity in pediatric kidney transplant recipients compared with chest physiotherapy alone. Methods: In this single-blinded randomized controlled trial, 30 pediatric kidney transplant recipients (8–18 years) were randomized to an experimental group (EG; n = 15) receiving combined IMT + EMT plus chest physiotherapy or a control group (CG; n = 15) receiving chest physiotherapy with sham training. Pulmonary function, respiratory and peripheral muscle strength, and functional capacity were assessed at baseline and after 8 weeks. Results: Significant time × group interactions were observed for pulmonary function parameters, with greater improvements in the experimental group (FVC: + 11.53 vs. + 1.06; FEV₁: + 8.40 vs. − 1.06; PEF: + 10.20 vs. − 3.13; all p < 0.01). Maximal inspiratory and expiratory pressures increased more in the experimental group (MIP: + 8.66 vs. + 4.13 cmH₂O; MEP: + 12.73 vs. + 2.06 cmH₂O; p < 0.05). Functional capacity (6-min walk test) improved in both groups but was significantly greater in the experimental group (+ 49.46 m vs. + 13.33 m; p = 0.006). No significant between-group differences were observed in exercise-related dyspnea or fatigue. Conclusions: Combined IMT + EMT integrated with chest physiotherapy significantly improved pulmonary function, respiratory muscle strength, and functional capacity in pediatric kidney transplant recipients, suggesting it is a valuable adjunct in post-transplant rehabilitation.