This randomized controlled trial was approved by the Ethical Committee for Human Research at the faculty of Physical therapy, Cairo University. The study was registered at the Pan African Clinical Trials Registry with registration No. PACTR202111663993438. Participants’ parents/legal guardians provided written informed consent before the study was conducted.
A sample of participating children with spastic hemiplegia was recruited from the Outpatient Clinic of Faculty of Physical Therapy, Cairo University, and National Institute for Neuromuscular System. They were evaluated by the examiner and included if they were diagnosed as spastic hemiplegia, their ages ranged from 6 to 13 years, according to gross motor function classification system-extended and revised (GMFCS-ER), they were at a level of motor function between I and II , and able to understand and follow instructions given in exercise program. Participants were excluded if they had significant mental or behavioral disorders, any associated disorders such as visual or auditory problems, fixed deformities of the lower extremities any musculoskeletal surgery, or injection by botulinum toxin in the lower limbs in the past 6 months before intervention  and unstable seizures.
Before starting the intervention, 40 children were randomly assigned to one of both groups process using sealed opaque envelopes. The examiner prepared 40 sealed envelopes, each including a card identified as group I or II. Each legal guardian of child was asked to choose a closed envelope to determine whether he/she was allocated into group I (N = 20, 13 boys and 7 girls) or group II (N = 20, 10 boys and 10 girls). Children in group I received functional resistance exercise program, while those in the group II received eccentric muscle control exercise program.
Weight and height were recorded for each child; then, each child’s functional ability and dynamic balance were evaluated individually before and after 6 weeks of treatment by the same examiner who was blinded in terms of group assignment.
Functional ability evaluation
Functional ability was assessed by gross motor function measure (GMFM) which is a five-level classification system. It is valid in assessing the child’s current motor functions and consists of 88 items related to gross motor abilities divided into five dimensions: lying and rolling (17 items); sitting (20 items); crawling and kneeling (14 items); standing (13 items); and walking, running, and jumping (24 items) . It was used to assess the child’s motor performance before and after treatment. Among the 5 domains, total scores in the domain (gait, running, and jumping) were assessed in this study. The examiner explained each item for each child and his parent. The tasks were done according to the instructions illustrated in the GMFM manual. The child began to perform each item while the examiner was observing the child’s ability to perform the task then gave him a score that ranged from 0 to 3 where 0 = could not do, 1 = initiated (˂ 10% of the task), 2 = partially completed (10 ˂ 100%of the task), and 3 = task completion. After completing all tasks, the examiner calculated the score for each child by dividing the total score by 72. Evaluation of each child took from 20 to 30 min.
Dynamic balance evaluation
Functional reach test was used to assess dynamic balance. It was performed with a leveled yardstick that was attached to the wall at the level of the patient’s acromion of the unaffected arm while sitting in a chair . The forward reach test is as follows: the child was seated next to but not touching the wall. The examiner instructed the child to raise his arm forward until it was parallel to the floor, and then the examiner gave the child verbal instructions and demonstrations to reach forward without touching the yardstick. The initial reach was measured with the upper extremity flexed to 90° using the placement of the third metacarpal along the meter stick ; then, the examiner measured the distance in centimeters from the tip of the acromion process to the tip of the middle finger. After the child took the starting position, the examiner instructed him to reach as far as he could forward without falling while maintaining a fixed base of support. The side reach test is as follows: the examiner instructed the child to raise his arm lateral until it was parallel to the floor. The initial reach was measured with the upper extremity abducted to 90° using the placement of the third metacarpal along the meter stick; then, the examiner measured the distance in centimeters from the tip of the acromion process to the tip of the middle finger. After the child took the starting position, the examiner instructed him to begin leaning as far as possible laterally without rotation while maintaining a fixed base of support. The examiner measured the maximum distance the child reached in centimeters. Scores were determined by calculating the difference between the start and end position of the reach.
The treatment was conducted by an experienced physical therapist. Children in both groups received 3 sessions per week for 6 weeks. In the remaining 3 days of the week, the mothers of included children were instructed to perform a home routine program, and a diary was kept to follow the application leaving a day off for rest.
Group I: Children in this group received a designed physical therapy program in addition to functional progressive resistance exercise. The designed physical therapy program focused on (1) facilitation of postural stability and balance in form of stimulation of righting and equilibrium reactions to improve the postural mechanism by balance bar, single leg balance with bar and walking in a stride line, (2) closed and open environment gait training as overcoming obstacles and walking in different floor styles, and (3) walking up and downstairs , in addition to functional progressive resistance exercise which consists of sit to stand, half-kneeling standing, and side step up. Children in that group were trained three times per week for 6 weeks. The session starts with warm-up exercise (range of motion, mobilization, stretching) which was done for 3 min, then resistive exercise for 25 min, and finally cooling down exercise (range of motion, mobilization, stretching) which was done for 2 min. All exercises were performed in 1–3 sets of 8–12 repetitions, with a 30-s to 1-min rest in between the sets. According to each subject’s performance, both weight and repetition were increased and progressed.
Sit-to-stand bilateral exercises were performed from sitting on a chair (no armrests, no backrest) with the hips at 90° and knees at 90° flexion (thigh parallel to the floor) and feet flat on the floor. The therapist used weight on the child's pelvis to add resistance. From the starting position, the therapist instructed the child to stand up slowly from the chair.
Half kneeling standing: the child was seated in a half-kneeling position without any external support. The therapist used weight distally at the child’s ankle on the affected side. From this starting position, the therapist instructed the child gradually to push his affected leg forward to stand up while the weight is shifted forward on the front leg
Side step-up exercise: the starting position of the child was standing; the therapist used weight distally at child’s ankle on the affected leg as resistance. The therapist asked the child to raise his affected leg and climb up a 15-cm staircase sideways 
Exercise repetition (i.e., set) was five times in the first 2 weeks then increased to 10 times in 3–4 weeks and 15 times in 5–6 weeks. Weight was increased according to subject’s participation, 5% weight in 1–2 weeks, 10% weight in 3–4 weeks, and 35% weight in 5–6 weeks, based on their body weight.
Group II: Children in this group received a designed physical therapy program in addition to eccentric muscle control exercise that included 4 exercises:
Standing to sit: the child stood erect with the neck in a neutral position, back extended, hand beside the body, knee extended, and feet flat on the floor. The therapist asked the child to sit on a chair slowly with back, knees, ankle flexed at 90 angles.
Standing and shifting weight anterior: the child stood erect; the therapist asked the child to shift weight anteriorly slowly
Sitting and returning to crock lying: the child was positioned sitting on matt with the neck in a neutral position, back erect, knee extended. The therapist asked the child to return to the crock lying position gradually
Standing and kicking a large ball: the child was positioned in front of a mirror; then, the therapist asked the child to kick a large ball backward slowly on a specific target then return to starting position. Each exercise was done 5 times, and 10 sets were performed with rest in between sets
Unpaired t-test was conducted for comparison of subject characteristics between groups. Chi-squared was carried out for comparison of sex distribution between groups. Mann–Whitney U test was conducted for comparison of GMFCS between groups. Normal distribution of data was checked using the Shapiro–Wilk test for all variables. Levene’s test for homogeneity of variances was conducted to test the homogeneity between groups. Unpaired t-test was conducted to compare the functional reach distance and GMFM-88 between groups. Paired t test was conducted for comparison between pre- and post-treatment in each group. The level of significance for all statistical tests was set at p < 0.05. All statistical analysis was conducted through the Statistical Package for Social Studies (SPSS) version 25 for Windows (IBM SPSS, Chicago, IL, USA).