Frog Reverse Hyperextension
Lie facedown on a flat bench and grasp it with both hands.
Flare the knees out wide and connect the soles of your feet.
Raise the legs to get full hip extension, hold at the top for 1-2 seconds and squeeze the glutes as tight as possible.
Slowly descend the legs and return to the starting position.
Note: Although this is called a "hyperextension", you want to make sure the spine is neutral and without an exaggerated anterior pelvic tilt.