Context-related variant of a single leg step up.

The goal is to land in the triple extension position as fast as possible, i.e. end-position-stabilization. A plate is swung overhead hence creating a perturbatory momentum the muscles of the trunk and spine have to control for.

In order to explosively step up from the unstable BOSU-ball ankle-stiffness is crucial. Sufficient stiffness in plantar-flexion enables the surrounding fascial structures to store and release elastic energy fast.

Re-assess your posture after each rep, try to follow the trajectory from the plantar-flexed foot upward behind your sternum.