Kinematic synergy of speed reduction during stair descent.

: This study aimed to quantify multi-segmental coordination using Uncontrolled Manifold (UCM) analysis to examine the effect of speed reduction on the control of stair descent. : Twenty healthy participants performed stair descent at a self-comfortable pace for normal speed conditions and at a slow speed set to a metronome rhythm of 60 beats/min. UCM analysis was separately conducted for the center of mass (COM) and swing foot, with anteroposterior and vertical movements designated as task variables, and segment angles defined as elemental variables.