Abstract
The aim of the present study was to compare isokinetic muscle performance of the knee extensors including surface EMG during repetitive maximum contractions between children with hemiplegic CP and healthy controls. A group of children with hemiplegic cerebral palsy (CP) (16 boys and eight girls; mean age 11 years with SD 2; range 7 to 15 years) and a control group(14 boys and eight girls; mean age 10 years with SD 2; range 7 to 15 years) participated. The relationships between maximum peak torque and the surface electromyography (EMG) variable root mean square (RMS) were obtained during 100 concentric knee extensions at 90°/s. Surface EMG was recorded from rectus femoris, vastus lateralis, and biceps femoris. The children with CP were also tested using Gross Motor Function Measure (GMFM). There were no differences between the groups in muscle endurance for the younger children. The results indicated that the children with CP had less strength enhancement in the hemiplegic leg during puberty. Peak torque correlated with GMFM and with RMS in rectus femoris and vastus lateralis. Co-activation was found in biceps femoris, but it did not affect muscle strength.