The Effects of Lower Limb Progressive Functional Strength Training Protocol on Body Functions and Activity in Children With Unilateral Spastic Cerebral Palsy: a Single-blind Randomized Controlled Trial

Cerebral palsy (CP) describes a group of disorders in the development of movement and posture, causing activity limitations, which are attributed to non-progressive disturbances that occurred in the developing brain. It is the most common cause of movement disability in childhood. Children with CP may experience a variety of impaired muscle functions, such as spasticity, muscle weakness, and loss of selective motor control. Muscle structural changes are caused to activate of mechanisms that are limited function with growing and maturation. The weakness found in children with CP is attributable to both altered neural mechanisms and muscle tissue changes. Several factors affect the level of weakness found in the muscles of children with CP. First, weakness may differ between proximal and distal limb muscles. Stackhouse et al. found that the maximum voluntary contraction (MVC) was more impaired in the plantar flexors than the quadriceps of children with mild CP compared with controls. Second, the peak torque may vary according to the velocity of limb movement. Peak torque of the knee flexors and extensors in 24 children with CP was found to decrease with increasing velocity on an isokinetic machine. Third, peak torque may vary according to muscle length. An isokinetic study of 44 children and young people with CP found that peak torque in the hip abductors occurred when the muscle was in a lengthened position with the leg still in adduction. Fourth, the type of contraction was found to consistently affect the peak torque in both children with CP and those who are typically developing, with eccentric force being greater than concentric force in the same muscle. Although all impaired muscle functions limit the performance of daily life activities and participation in a child with CP, a recent study has shown that muscle weakness showed a stronger association with mobility limitations in children with CP than spasticity. Strength training for these children is, therefore, expected to improve or maintain their strength and functional performance.