Vertical stiffness and balance control of two-legged hopping in-place in children with and without Down syndrome

Our findings suggest that children with DS might not be able to continuously hop in-place until the age of 7 years old, and were unable to hop for as long in duration as their TD peers. Children with DS self-selected a faster hopping frequency, and demonstrated an increased medial-lateral center-of-mass movement during the stance phase of hopping, suggesting reduced balance control. Moreover, children with DS were unable to correctly modify their hopping frequency when cued by a metronome and exhibited an inability to modulate whole-body vertical stiffness and constrain horizontal or vertical movement. These results demonstrate the utility of a future hopping intervention to improve whole-body vertical stiffness and balance control in children with DS.