For the Bicycle Crunches, lay comfortably on your back on the ground. Next, place your hands behind your head so that your elbows are facing away from your body. To perform the exercise, simultaneously bring one knee up to your chest, while the opposite elbow comes across your body. The two body parts should touch before returning to their starting position. Next, repeat the same motion with the opposite limbs. When in full speed your limbs should seem as if they are pumping a bicycle. Repeat the motion for the allotted amount of time and then rest.
This exercise focuses on your core. When twisting your torso in the contracted position you are emphasizing the oblique muscles on the sides of your body.