Dragon Flag Negative

Lie on a bench, hands gripping behind your head for anchor, and get your whole body into a straight line balanced on your shoulder blades, hips and knees locked rigid, feet pointed toward the ceiling. From that top position, lower your body as one solid piece, resisting the fall with your abs rather than letting your hips lead or your knees bend. The moment your lower back can't hold the line and your hips start to sag, that's as far down as this goes — stop there rather than crashing the rest of the way. Reset at the top and lower again, treating the descent itself as the entire exercise.