Plank with feet in the straps, knees driving fast.
Keep your hips low and level, don't let them pike up as you climb.
With both feet hooked in low straps, every knee drive is powered by the legs while the suspended base removes all the friction and support the floor usually provides. The quads fire each drive and the glutes stabilise the hips, holding them low and level as the legs alternate at speed for the whole timed set. It earns a place as brutal leg-driven conditioning, the strap suspension forcing clean knee drives because any sloppy rep sets the whole system swinging.
On the floor your toes support and reposition your weight. In straps your feet hang free, so every knee drive must be controlled by your legs and trunk while the cradles try to swing.
Control first, then speed. Fast climbing with piking hips or swinging straps trains nothing, quick clean drives with a flat body line train everything.
Drive the knees toward your chest, not toward the floor, and keep pressing tall through your shoulders. If the pike persists, slow your pace until the line holds.
