The development of strong core muscles is the focus of Pilates, an exercise regimen developed by Joseph Pilates in the early part of the twentieth century. Pilates, a physical trainer, created these exercises when he worked in Europe after World War I helping to rehabilitate soldiers. His exercise system focused on strengthening the muscles the soldiers could use when their arms and legs were in traction.
Because the soldiers were in bed, Pilates used pulleys that moved their limbs for them as they contracted and strengthened their core muscles to initiate movement. This sounds complicated, but you can easily imitate what he did. First, lie on your back and press your lower back gently toward the floor. Now raise your arms and legs above the floor while still engaging your abs. You'll see how much strength it takes just to stay in this position for a few minutes. Pilates theorized that by strengthening the muscles of the back and front torso, he could help an injured man gain better use of all of his muscles and better control his entire body. In fact, Pilates was first called Contrology. Pilates moved to the United States and adapted his work for dancers, who found his techniques helped their strength and performance.
Today, Pilates students use Reformers, machines that have pulleys and a moving board, which require users to engage their core muscles as they use the resistance of the pulleys with their limbs to move their torso, which rests on the moving board. Reformers pretty much simulate what Pilates did with the soldiers who were confined to bed. But because Reformers are cumbersome and expensive, these moves have been adapted to floor exercises, sometimes called mat routines because they are done with a mat placed on the floor. They still require you to engage your core muscles and move your limbs, but you don't have the added resistance of pulleys. On the other hand, once you become very strong, you can use resistance bands to add a further challenge to your routine.