The Effect of Functional Inspiratory Muscle Training versus Inspiratory Muscle Training on Trunk Control and Respiratory Functions in Individuals with Chronic Stroke: A Randomized, Controlled, Double-Blind Study.

Abstract

To compare the effects of Functional Inspiratory Muscle Training (FIMT) with Inspiratory Muscle Training (IMT) in individuals with chronic stroke. Prospective, randomized controlled, double-blinded trial SETTING: Department of Physiotherapy and Rehabilitation PARTICIPANTS: Forty-two individuals with chronic stroke (mean age 62.9 years, 36.4% female for FIMT group; mean age 60.3±8.3 years, 40.9% female for IMT group) completed the study. Both groups received Neurodevelopmental Therapy (NDT) three times per week for eight weeks. The FIMT group performed inspiratory muscle training simultaneously with NDT-based functional exercises (e.g., bridging, kneeling, weight transfer), while the IMT group performed inspiratory training separately, combined with NDT in the same session. All participants also completed a home-based IMT program twice weekly. The primary outcomes were the Trunk Impairment Scale (TIS) and maximal inspiratory pressures (MIP). Secondary outcomes included Trunk Control Test (TCT), maximal expiratory pressures (MEP), respiratory endurance (Incremental Threshold Loading Test), spirometry values (FEV₁,FVC), balance (Berg Balance Scale), gait (Timed Up and Go, 10-Meter Walk Test), core muscle activity (PRONE test), functional capacity (6-Minute Walk Test), and independence (Barthel Index). Both groups showed significant improvement in most outcome measures following training. However, the FIMT group demonstrated notably greater gains in trunk control (TIS, TCT), respiratory muscle strength and endurance (MIP, MEP, ITL), balance, walking speed, and transversus abdominis activity (p<0.05). The mean between-group difference in TIS change was 2.62 points (95%CI 1.67-3.57), with the lower bound of the confidence interval exceeding the smallest worthwhile effect (0.31). FIMT also yielded superior improvements in MIP (7.48 cmH₂O, 95%CI 2.43-12.52). No significant differences were observed between groups in 6MWT distance, spirometry results, or Barthel Index scores. FIMT produced greater improvements than IMT in trunk control, respiratory muscle function, balance, and gait speed in individuals with chronic stroke, suggesting it as a promising rehabilitation approach.