Bicycle Crunch Lie flat on the floor with your fingers laced behind your head. Slowly raise your shoulders and neck off the ground (without pulling with your hands); lift your legs so they're a few inches off the floor. Crunch forward and to the left, at the same time bringing your left knee up until it meets your right elbow just above your lower abdominals. Slowly return your arm and leg, then perform this same movement on the other side so your left arm meets your right knee. That's one rep. Beginners should complete 10 reps and more advanced people should complete 20 reps. Image Source: POPSUGAR Studios