Isometric voluntary force production and relaxation capacity of the quadriceps femoris (QF) muscle was compared between 12 children with spastic diplegic cerebral palsy (CP) and healthy controls, age 10–11 years. Children with CP had less (p < .05) maximal voluntary-contraction force, voluntary activation, and rate of force development than controls. Visual reaction to contraction did not differ significantly in measured groups, whereas the reaction time to relaxation and halfrelaxation time were longer (p < .05) in children with CP. The authors concluded that in children with CP, the capacity for rapid voluntary force production and relaxation is reduced to a greater extent than isometric maximal force.
The authors are with the Institute of Exercise Biology and Physiotherapy, Estonian Center of Behavioral and Health Sciences, University of Tartu, 51014 Tartu, Estonia.