The primary aim of this study is to investigate the effectiveness of Schroth training and the multidimensional effects of adding Pilates-based exercises to Schroth training in individuals with adolescent idiopathic scoliosis. Specifically, the study aims to evaluate the effects of Pilates-based exercises combined with Schroth training on lung capacity, trunk muscle strength, proprioception, trunk rotation, and posture. In addition, it seeks to examine the impact of the intervention on important functional and psychosocial outcomes, including quality of life, perceived cosmetic deformity, and pain threshold.

This study is expected to contribute to the existing evidence on the use of Pilates exercises in combination with Schroth exercises for individuals with adolescent idiopathic scoliosis by providing a comprehensive evaluation of the effects of this combined intervention. The findings are intended to provide guidance for clinicians and researchers regarding the combined use of different exercise approaches in the management of adolescent idiopathic scoliosis. Furthermore, the study aims to explore the potential benefits of integrating the Schroth method with Pilates as a holistic treatment approach for scoliosis management.

Scoliosis is a three-dimensional spinal deformity characterized by a lateral curvature greater than 10° measured using the Cobb angle, accompanied by vertebral rotation . Approximately 80% of idiopathic scoliosis cases occur during adolescence . Adolescent idiopathic scoliosis (AIS) typically develops between the ages of 10 and 18 years. Several factors, including the initial curve magnitude, curve location, apical vertebral rotation, and age, have been identified as risk factors for curve progression .

Treatment of AIS depends on the severity of the spinal curvature and may include bracing, exercise-based interventions, or surgical treatment. The International Society on Scoliosis Orthopaedic and Rehabilitation Treatment (SOSORT) classifies scoliosis exercise approaches under the category of Physiotherapeutic Scoliosis-Specific Exercises (PSSE). Among these approaches, the Schroth method, which is based on rotational angular breathing, is one of the most widely used and extensively studied treatment methods in the literature . revious research has demonstrated that Schroth therapy may contribute to reductions in Cobb angle and improvements in quality of life in adolescents with idiopathic scoliosis. In addition, Schroth-based exercises have been associated with enhanced thoracic and lumbar proprioception.

The literature has associated increases in thoracic curvature, measured by the Cobb angle, with reductions in pulmonary function. Although these reductions have not yet been classified as abnormal by the American Thoracic Society, decreased pulmonary function has been observed even in individuals with mild spinal curvatures. It has been estimated that every 4-5° increase in Cobb angle is associated with approximately a 1% reduction in total lung capacity .

Pilates, originally referred to as "Contrology", was developed by Joseph Pilates and has become widely practiced in both fitness and rehabilitation settings . Although relatively few studies have investigated the effects of Pilates on scoliosis, existing evidence suggests that it may have beneficial effects in this population . Gou et al. reported that Pilates exercises reduced the Cobb angle while improving quality of life and trunk range of motion.

In a 12-week intervention study, Khaledi et al. compared Schroth exercises combined with asymmetric spinal stabilization exercises and found no significant between-group differences in back muscle endurance. Nevertheless, numerical improvements favored the combined exercise group compared with the control group. Similarly, previous studies were compared Schroth exercises with core stabilization exercises in adolescents with idiopathic scoliosis and found that participants receiving Schroth training demonstrated significantly greater improvements in perceived cosmetic appearance than those performing core stabilization exercises. Despite these promising findings, the level of evidence supporting the effectiveness of Pilates exercises in the management of scoliosis-related deformities remains limited. Pilates exercises have been reported to reduce asymmetrical posture in individuals with mild scoliosis and a low risk of progression. Both Schroth and Pilates exercises are considered to have positive effects on lung capacity, trunk proprioception, trunk muscle strength, and quality of life in individuals with AIS. However, previous studies have primarily investigated the effects of these exercise approaches separately. Based on the current literature, no study has evaluated the effects of Pilates-based core stabilization exercises added to Schroth training in individuals with adolescent idiopathic scoliosis. Therefore, further research is needed to investigate the potential benefits of this combined intervention.

Inclusion Criteria:

• Aged 10-18 years.
• Diagnosed with adolescent idiopathic scoliosis by a physician.
• Cobb angle between 10° and 45°.
• Willingness of both the participant and their parent/legal guardian to participate in the study.
• No additional rheumatologic, neurological, or orthopedic disorders.
• No scoliosis-specific treatment received within the previous 6 months.

Exclusion Criteria:

• History of scoliosis or spinal surgery.
• Scoliosis secondary to neurological, congenital, or other non-idiopathic causes.
• Any contraindication to exercise.
• A spinal curve with an apex at T12-L1.
• Presence of cognitive impairment that would interfere with study participation or assessments.
• Current brace treatment. Participants who are eligible for bracing but have not been prescribed a brace by their physician or who decline brace treatment despite being eligible will remain eligible for inclusion.