Anticipatory postural adjustments in a bimanual load-lifting task in children with Duchenne muscular dystrophy

We investigated the consequences of a progressive damage to the muscular system on the organization of anticipatory postural adjustments (APA) in children with Duchenne muscular dystrophy (DMD). We used a bimanual load-lifting task requiring the stabilization of the forearm position despite its voluntary or imposed unloading. Eight children with DMD from 4 to 11 years of age were compared to eight typically developing (TD) children. Elbow angle and multiple surface EMGs were recorded and assessed the use of APA. The muscle weakness did not impair (1) the proprioceptive afference and the motor efference constituting the unloading reflex; and (2) the use of an anticipatory function in children with DMD. However, APA used for the forearm stabilization were less efficient in the group of children with DMD. We conclude that in DMD the muscular weakness could be a restraint to the efficiency of APA with respect to TD children.