Lower limb muscle kinetics during Y-balance test between children with and without developmental coordination disorder

Abstract

Despite the atypical muscle activation patterns exhibited in children with developmental coordination disorder (DCD) during static postural control tasks, no studies to date have investigated if this pattern is shown in dynamic postural control conditions. This study aimed to evaluate the leg muscle patterns during the lower quarter Y-balance test (YBT-LQ) between children with and without DCD. Forty-eight children with DCD (mean age ± SD = 8.03 ± 1.10 years; 37 males and 11 females) and fifty-one children with typical development (mean age ± SD = 7.82 ± 1.06 years; 32 males and 19 females) were allocated to the DCD group and control group, respectively, after screening by two physiotherapists. Rectus femoris, biceps femoris, tibialis anterior and gastrocnemius medialis muscle activations (of the weight-bearing leg) were measured by surface electromyography and foot contact switches during the YBT-LQ anterior, posteromedial and posterolateral reaches. Children with DCD revealed a lower YBT-LQ score (P < 0.001) when compared to the control group for all reach directions. Moreover, the posteromedial and anterior reach directions revealed different muscle activation patterns with a lower gastrocnemius medialis peak activation (P = 0.029) and a shorter gastrocnemius medialis muscle time-to-peak duration (P < 0.05), respectively, in children with DCD compared with the controls. Children with DCD exhibited a less competent YBT-LQ performance and dissimilar leg muscle activation patterns in dynamic balance situations. They may adopt a different lower limb neuromuscular control than typically developing children to compensate for the balance deficits. Rehabilitation interventions for children with DCD should therefore incorporate dynamic postural control elements with an emphasis on phasic neuromuscular control of the weight-bearing leg.