Muscle Thickness in Lower Extremity and Locomotor Functions in Children With Down Syndrome and Typical Developing...

Children with Down syndrome (DS) have deficits in motor skills that lead to stereotypical changes in the characteristics and adaptations of their movement. The aim of the study was to investigate locomotor characteristics and muscle thickness of the selected muscles in the lower extremity and the relationship between muscle thickness and locomotor parameters in children with DS and typically developing peers.

Children with DS (n = 18; age: 5.36 ± 0.60) and typically developing (TD) (n = 30; age: 5.62 ± 0.60) aged 4-7 years participated. Lower limb muscle thickness was assessed through B-mode ultrasound. The GAITRite system evaluated gait and running spatiotemporal parameters, using linear regression to determine the strength of the relationship between muscle thickness and these parameters.

Compared to the TD group, the DS group had significantly less lower limb muscle thickness and differed significantly in gait and running parameters (p < 0.05), except for gait stance and swing percentages. Tibialis anterior muscle thickness predicted step length in TD (1.546 ± 0.081) and DS (1.501 ± 0.148), respectively, explaining 16.3% and 31.4% of gait, and in DS, 26.8% of running.

Muscle thickness may serve as an indicator of muscle strength and coordination, contributing to the understanding of their impact on locomotor performance in DS children, particularly with regard to the tibialis anterior muscle, which is essential for dorsiflexion and foot placement control. The prioritisation of stability for gait and running is essential due to reduced velocity, increased step width and shorter step length in DS children.