Butterfly Sit Up

In this midrange exercise your arm muscles provide you with a little bit of momentum to help to get you off the ground. You also open them up in overhead position which engages the upper back. Start lying with feet flat on the ground, knees at an angle, arms crossed in towards your chest. Using your ab muscles, bring your upper body off the ground as you open your arms into goal post position, then slowly lower yourself back down to return to starting position.