Heels in the straps, run it out from a bridge.
Keep your hips lifted the entire time, the second they drop, your hamstrings stop working.
From a locked bridge, the runner alternates heel drags in a continuous cycle, each hamstring curling the strap in while the opposite leg extends, like sprinting on your back. The glutes never get a rest, holding the hips high through every switch, because the moment they drop the hamstrings lose their line of pull entirely. It earns its place as hamstring conditioning with a sprint-specific flavour, training the exact curl-and-extend rhythm the legs use at speed.
Rhythm. The pull-in works one full rep at a time, the runner cycles both legs continuously like a running motion, which makes it more of a coordination and conditioning challenge at speed.
Only as fast as your hips stay motionless. A quick cycle with a rock-solid bridge is the goal, if your pelvis starts bouncing, slow down until it stops.
They are holding the bridge and curling at the same time, which is a big ask. Shorten your sets, squeeze the glutes harder to share the hip work, and progress volume slowly.
