Effect of Isokinetic Training on Knee Muscle Strength and Balance Control in Children with Developmental Coordination Disorder: A Randomized Controlled Trial

Background: Children with Developmental coordination disorder (DCD) have lower knee muscle strength and altered timing of postural muscle contraction that might increase the risk of falls, limit activity participation, and affect motor skill development Objective: The purpose of this study was to investigate the effect of isokinetic training on knee muscle strength and functional activities in children with developmental coordination disorder. Design: Randomized controlled trial. Subjects: Sixty children with DCD from both sexes with age ranged from eight to 12 years were randomly assigned to either the isokinetic training intervention group or the control group. In addition to the DCD children, the study included thirty typically developing children who received no training as normal controls. Methods: Patients in the isokinetic group (n=30) participated in the isokinetic training program for 12 weeks for quadriceps femorisand hamstring muscles, 3 times per week. Each set consists of 10 repetitions concentric contraction at an angular velocity of 150º/s and patients were allowed 3min of rest between sets. Main Measures: Isokinetic peak torques of quadriceps femoris and hamstring musclesat two test speeds (60º/s) and balance control were assessed before isokinetic training and again within two weeks of its completion using an isokinetic machine and Bruiniks Oseretstity test of motorproficiency, respectively. Results: Patients in isokinetic group showed a significant improvement in quadriceps femoris and hamstring muscles strength specifically at 60°/s and was as high as that of the normal control children. Moreover, balance controlin isokinetic group was better and was comparable to that of the normal control group after training. Conclusions: Children with DCD who undergo a 3-month program of isokinetic training experience improvements in isokinetic knee muscle strength at 180º/s and balance control.