## 2 Materials and Methods
### Patients  
The participants attended the Special Education School for Children with Cerebral Palsy from the Red Cross of Valencia (Spain). Inclusion criteria were that they were aged between 4 and 21 years old, with a diagnosis of CP, level IV (severely limited self-mobility and needing to rely on powered mobility or extensive assistance for movement) or level V (extremely limited voluntary movement and lack of independent mobility, requiring full assistance for posture and transport in all settings) of the GMFCS, spasticity of \(\geq\)1 on the Ashworth scale, that they were in compliance with the anthropometric and safety parameters indicated in the ATLAS 2030 exoskeleton (Marsi Bionics, Madrid, Spain), and that they had a level of strength of at least a level 1 to meet the intention mode of the ATLAS 2030 exoskeleton. The exclusion criteria were having a musculoskeletal condition that made physical intervention contraindicated (such as a fracture), a skin condition that makes water immersion contraindicated (such as an open wound or pressure ulcer), and uncontrolled epilepsy. After applying these criteria, 3 children were included.  
Participant 1. Female, 9 years old. She presented spasticity in the four limbs (currently treated with a baclofen pump), and limited ability to hold her head upright, mostly due to muscle weakness and dystonic body movements, which increased when she became very euphoric. Although she intended to move voluntarily, the dystonic movements limited her movement, which had little or no motor control and was completely uncoordinated. She was able to stand with support from another person, but she was unable to stand independently. She could walk when held under the armpits, supporting her entire torso,but could not walk independently in a walker due to her dystonia and the support needed. She had no knee flexion contracture, but the popliteal angle was reduced. She did have a flexion contracture in her right elbow. In terms of expression, she was communicative but often struggled to speak and express herself due to her musculoskeletal condition.  
Participant 2. Male, 6 years old. He presented with spasticity showing a predominantly flexor pattern, although he did have the ability to hold the head against gravity and move in different directions in space. He showed good trunk control and was able to crawl at home. Occasionally, he could walk with support or use a walker, although his gait was slow and poorly coordinated. He had bilateral knee flexion contractures (less than 20\({}^{\circ}\)) and both hips exhibited adduction and internal rotation. He was nonverbal but demonstrated communicative intent, although it was occasionally limited.  
Participant 3. Female, 9 years old. Her symptoms included spasticity with a predominantly extensor pattern. Her upper limbs were held in internal rotation, pronation, and ulnar deviation, with clenched fists when tense. Her lower limbs tended towards an internal rotation pattern, but without knee or hip flexion contracture. She was unable to hold her head against gravity most of the time, but when controlled, she could turn her head to both sides. There was no evidence of active voluntary limb movement; limb activity was spasmodic and appeared to be triggered by fear or excitement. Her cognitive level and communicative intent were low, but she could express pleasure and displeasure in different daily routines.  
A patient flow diagram for the selection, assessment, and intervention process is provided in Figure 1.  
Figure 1: Patient flow diagram.