RÉSUMÉ
Introduction: Cerebral Palsy (CP) is characterized by a disorder of posture and movement, commonly leading to disabling orthopedic alterations, including muscle shortening, especially in the lower limbs. Stretching methods, performed gradually, are necessary to delay the impairment in function from muscle shortening. The use of serial casting aims to promote proper alignment, and an ideal and stable support base, in addition to better bone and joint health, leading to better posture, mobility, muscle function, and, subsequently, increased fitness and health.Objective: evaluate range of motion, postural control, and motor performance in children with CP, using serial casting, as well as to measure its effect on fitness through the autonomic nervous system (ANS).Methods: Sixty children and adolescents with CP, of both sexes, 3 to 12 years of age, will be divided into three groups: Groups A, B, and C, with 20 individuals each. Group A will use serial casting, Group B will use the orthosis continuously (with removal only allowed for bathing), and Group C will use the orthosis in their daily routine. Range of motion of the ankle of first and second resistance levels (R1 and R2), gross motor function measure (GMFM), and balance (measured by BERG scale) will be used in the initial and final assessments, and after 6 months and one year of follow-up. Timed-up-and-go (TUG), load distribution (baropodometry), motor performance measured through a real basketball game and the virtual MoveHero game, analysis of body angulation with "mydartfish", and cardiac autonomic modulation through heart rate variability will be assessed in three different situations: barefoot, with orthosis, and with casting.Conclusion: Serial casting demonstrates the potential to produce positive results in the treatment of individuals with CP regarding better alignment, with consequent motor and autonomic improvement.