Roller reverse crunch

Lie flat on your back with your arms extended straight above your head and your legs straight out in front of you. Place the roller between your feet and grip it with your toes. Engaging your abs, lift your legs off the ground and curl your knees towards your chest, rolling the roller towards your body. Pause for a moment at the top, then slowly lower your legs back down to the starting position, rolling the roller away from your body. Repeat for the desired number of repetitions.