Lie flat on your back with your arms fully extended towards the ceiling, holding a weight in your hands.
Raise your legs straight up in the air so that the flats of your feet are facing the ceiling.
Keeping your arms straight (locked at the elbows), lift your shoulders off the mat, pushing the weight toward your feet. The crunch should feel like a small pulse upwards, coming from your core.
Lower your chest and shoulders back down, keeping your arms and legs extended towards the ceiling.