## 1 Introduction  
Cerebral palsy (CP) is the leading cause of physical disability in childhood, occurring in 2.11 out of every 1000 live births [1]. It describes a group of lifelong disorders that affect the child's motor, cognitive, and/or sensory development and may have associated pathologies such as musculoskeletal, digestive, respiratory, or pain disorders [2]. CP has a multifactorial origin and variable clinical presentation that has been classified by the \"Surveillance of Cerebral Palsy in Europe\" [3] as spastic (70-80% of the cases),dyskinetic (10-15%), ataxic (4%), or a mixture of these disorders. Children with cerebral palsy often have other disabilities that can affect their quality of life and life expectancy. They can also suffer secondary musculoskeletal problems which include spasticity, joint contractures, kyphoscoliosis, and hip subluxation [4]. Regarding the severity of musculoskeletal conditions, children with CP are classified using the Gross Motor Function Classification System (GMFCS), a standardized five-level clinical system (I-V) used worldwide to describe gross motor function and its evolution and prognosis [5]. The classification is based on functional performance in everyday activities including sitting, transfers, and mobility, where level I represents minimal impairment and level V represents severe impairment [6]. Spasticity seems to be one of the factors that can interfere with gross motor skills, particularly in children with severe forms of spastic CP [7]. Some muscles are more affected, and hamstring shortening tends to cause knee extension restrictions, both at initial foot contact and in midstance of gait. As a bi-articular muscle, the hamstring also tends to rotate the pelvis posteriorly [8]. It has been previously stated that maintaining hamstring length is important for reducing the risk of knee contractures since knee joint contracture has been associated with short hamstrings [9]. To address spasticity, joint deficits, and consequently the participation limitations of children with CP, there are several treatment options. One of the most used and pleasant treatments for them is aquatic therapy in warm water (32-35\({}^{\circ}\)) [10]. Immersion in hot water increases cerebral vascularization, generating positive effects in cortical activity and executive functions, and an increase in neurotrophic factors [11]. When combined with exercise, immersion in water is considered aquatic therapy, and various methods are available. One of the most used interventions in children with CP, due to its benefits, is the Halliwick method [12; 13]. Both water interventions provide sensory information, postural support, a sense of independence, and rotational movements that the children would not be able to experience in other environments [12]. In addition, these two interventions, through hydrostatic pressure and thermal effect, have been shown to reduce muscle spasms and improve range of motion [14]. These effects suggest a potential therapeutic role in neuromuscular rehabilitation and sensory integration therapies. Regarding functions related to movement and the musculoskeletal system, there is also strong evidence in favor of supported standing for its positive effects on range of motion and reduction of the risk of hip dislocation [15; 16] Moreover, previous evidence suggests that standing for 30 to 40 min a day can reduce spasticity, although not with a long-lasting effect [16]. Recently, there has been a significant increase in the use of robotic devices in neurological rehabilitation [17] in CP. The rationale behind robot-assisted gait training (RAGT) lies in the principles of task-specific motor relearning and neuoplasticity [17; 18]. Robotic systems also allow precise adjustment of training parameters and enable objective quantification of effort [17].