The Saw is a classical pilates exercise that increases the flexibility and strength of the core. Be careful not to turn this into a hamstring stretch. The goal of the exercise is to use the abdominal muscles to rotate the spine, then flex the spine over the leg scooping out the abdominals. If you have tight hip flexors or hamstrings, start sitting on a small cushion so you can begin the exercise in upright alignment. Watch this how to video and you'll be performing the Saw pilates exercise in no time.