Resisted Inspiratory Muscle Training Applied in Addition to PSSE-Schroth Exercises

Hacettepe University45 enrolled

Overview

This prospective randomized controlled trial will evaluate whether adding resisted inspiratory muscle training (IMT) to Physiotherapeutic Scoliosis-Specific Exercises (PSSE)-Schroth exercises provides additional benefits on clinical outcomes in individuals with adolescent idiopathic scoliosis. Participants will be randomly assigned to either PSSE-Schroth plus IMT or PSSE-Schroth alone. Both groups will receive supervised exercise sessions three times per week for 8 weeks (24 sessions). Outcomes will be assessed before and after the intervention and will include clinical measures (e.g., Cobb angle, angle of trunk rotation, Posterior Trunk Symmetry Index, The Walter Reed Visual Assessment Scale), respiratory muscle performance (maximal inspiratory pressure/maximal expiratory pressure, six-minute walk test) and related physiological parameters, functional performance (balance, 3D kinematics, plantar pressure analysis, isokinetic strength), sleep quality, and health-related quality of life (Scoliosis Research Society- 22, Italian Spine Youth Quality of Life). The study is expected to enroll approximately 45 participants.

Adolescent idiopathic scoliosis (AIS) is a three-dimensional spinal deformity that may adversely affect thoracic volume, respiratory mechanics, postural symmetry, balance, functional capacity, and health-related quality of life. While physiotherapeutic scoliosis-specific exercises (PSSE), including the Schroth method, have demonstrated clinical benefit, the evidence regarding the added value of integrating structured inspiratory muscle training (IMT) with PSSE remains limited, particularly in studies using comprehensive physiological and biomechanical outcome sets. This prospective, randomized controlled trial will investigate whether adding resisted IMT to a standardized PSSE-Schroth program provides additional improvements in clinical outcomes in adolescents with AIS. Eligible participants will be females aged 10-18 years diagnosed with AIS, with Cobb angle between 10° and 45°, angle trunk rotation (ATR) ≥5°, and skeletal immaturity criteria consistent with Risser ≤3 and Sanders ≤4. Participants with non-idiopathic scoliosis, recent spine surgery/major trauma, contraindications to exercise, relevant systemic/neurological conditions, or recent participation in PSSE/IMT programs will be excluded. Participants will be randomly allocated to one of two groups: (1) PSSE-Schroth plus resistance IMT or (2) PSSE-Schroth alone. Both groups will receive supervised sessions for 8 weeks, three times per week (total 24 sessions). The independent variable is the exercise protocol, and dependent variables include clinical measures. The trial aims to provide a multidimensional evaluation of the potential additive effects of IMT when integrated with PSSE-Schroth, offering clinically relevant evidence to refine conservative rehabilitation strategies for AIS.

Interventions

Physiotherapeutic scoliosis-specific exercises (PSSE-Schroth)OTHER

Participants will perform a standardized PSSE-Schroth exercise program under supervision. Sessions will be delivered three times per week for 8 weeks (total 24 sessions). Exercises will be individualized according to scoliosis pattern and clinical assessment

PSSE-Schroth + Resistance IMTOTHER

Participants will receive threshold-loaded inspiratory muscle training in addition to PSSE-Schroth. IMT will be supervised and performed three times per week for 8 weeks, aligned with the exercise sessions. Training will be progressed according to individual tolerance and protocol targets

Eligibility

Sex: FEMALEMin age: 10 YearsMax age: 18 Years

Medical Language ↔ Plain English

Inclusion Criteria: Female adolescents aged 10-18 years. Diagnosis of adolescent idiopathic scoliosis (AIS). Cobb angle between 10° and 45°. Angle trunk rotation (ATR) ≥ 5°. Risser ≤ 3 and Sanders ≤ 4. No scoliosis-related procedure within the last 6 months. No contraindication to exercise. Exclusion Criteria: Non-idiopathic scoliosis (neuromuscular, congenital, syndromic). Inability to achieve ≥80% adherence/compliance. History of spinal surgery or major trauma. Cardiopulmonary diseases contraindicating exercise. Neurological, rheumatological, vestibular, or systemic diseases. Acute musculoskeletal injury or impaired skin integrity. Participation in a regular PSSE-Schroth or IMT program within the last 3 months. Intellectual disability or communication difficulties preventing protocol adherence. Newly initiated brace treatment or high risk of non-compliance with brace management. Lack of informed consent.

Outcomes

Primary Outcomes

Six-Minute Walk Test

The Six-Minute Walk Test (6MWT) is a tool designed to assess functional exercise capacity, with a particular focus on individuals suffering from cardiopulmonary conditions. The distance walked in six minutes on a flat, straight course, typically 30 metres long, is recorded. The distance measured reflects submaximal exercise capacity. The 6MWT is a valuable tool in the assessment of disease progression, the evaluation of rehabilitation outcomes, and the determination of treatment response.

Time frame: Baseline and after 8 weeks (24 supervised sessions).

Change in Cobb Angle

Cobb angle will be measured on standard standing posteroanterior radiographs. The primary outcome is the change in Cobb angle from baseline to post-intervention.

Time frame: Baseline and after 8 weeks (24 supervised sessions).

Respiratory muscle strength - maximal inspiratory pressure (MIP)

Maximal inspiratory pressure (cmH₂O) will be measured using a digital manometer. The primary outcome is the change in MIP from baseline to after the 8-week intervention, and the between-group difference in this change (PSSE-Schroth + resistance IMT vs PSSE-Schroth alone).

Time frame: Baseline and Week 8 (end of 24 supervised sessions).

Secondary Outcomes

Angle of Trunk Rotation (ATR)

Angle of trunk rotation will be measured using a Bunnell scoliometer during the forward bend test. The outcome will be reported as change from baseline to post-intervention and compared between groups.

Time frame: Baseline and immediately after the 8-week intervention (24 sessions)

Posterior Trunk Symmetry Index (POTSI)

Posterior trunk symmetry will be evaluated using the Posterior Trunk Symmetry Index (POTSI). Change from baseline to post-intervention will be analyzed to assess the effect of adding inspiratory muscle training to PSSE-Schroth.

Time frame: Baseline and immediately after the 8-week intervention.

Walter Reed Visual Assessment Scale - Turkish version (WRVAS-TR)

Perceived trunk deformity will be assessed with the Turkish version of the Walter Reed Visual Assessment Scale (WRVAS-TR). The outcome will be the change in total score from baseline to after the intervention.