Spin your way to fitness with the fun, fast, fabulous Powerhoop. Slim your waist - flatten your tummy - strengthen your back - Increase your core stability - tone your glutes, hips, thighs! A revolution in fitness full circle training for your core muscles. Core muscles are the deep muscles and connective tissue that encircle the spine and provide structural support. Strengthening only one side will pull the spine out of alighnment therefore it's important to train front, back and the sides of our core.