Balance Assessment Scale and Strength Measurement Protocol to Measure Functionality in Adults With Spinal Deformity

Inclusion criteria pathological subjects: 1. Adult (\>18 years old) subjects suffering from a adult spinal deformity with sagittal or coronal plane misalignment diagnosed on EOS imaging. 2. Ability to walk at least 50 meters distance independently without a walking aid. 3. No documented neurological disease or vestibular lesion affecting balance nor a current history of musculoskeletal disorders of the lower extremities affecting motor performance. Inclusion criteria control group: 1. Adults (\> 18 year old) 2. No current history of back pain and spinal deformity. 3. Ability to walk at least 1000 meters distance independently without a walking aid. 4. No documented neurological disease or vestibular lesion affecting balance nor a current history of musculoskeletal disorders of the lower extremities affecting motor performance. Exclusion criteria ASD patients: 1. Age \< 18 years old and \> 79 years old 2. Absence of adult spinal deformity 3. Non-ability to walk at least 50 meters distance independently, with or without a walking aid. 4. Missing patient informed consent 5. Patients presenting with a neurological disease affecting balance other than Parkinson's disease such as stroke and/or Vestibular lesion 6. Patients with a history of spinal fusion surgery. 7. Patients with a current history of diagnosed musculoskeletal disorders of the trunk and/or lower extremities affecting the motor performance such as severe hip arthrosis with or without flexion contracture, severe knee arthrosis, severe ankle arthrosis, severe leg length discrepancy (\> 3 cm) Exclusion criteria control group: 1. Age \< 18 years old and \> 79 years old 2. Backpain and/or Sciatica at time of the study 3. Presence of adult spinal deformity leading to a pathological sagittal alignment 4. Non-ability to walk at least 1000 meters distance independently without a walking aid 5. Missing patient informed consent 6. Patients presenting with a neurological disease affecting balance such as Stroke, Parkinson's disease and/or Vestibular lesion 7. Patients with a current history of diagnosed musculoskeletal disorders of the trunk and/or lower extremities affecting the motor performance such as severe hip arthrosis with or without flexion contracture, severe knee arthrosis, severe ankle arthrosis, severe leg length discrepancy (\> 3 cm)