Heavy Bands are a product we use for distraction of the shoulder and hip. The big blue one is awesome at creating enough pull on the femur to relieve symptoms from hip impingement, tendonitis of the hip and more.
The Purple band is one I personally use for teaching the shoulder joint how to move properly through a previously painful range of motion without pain. Compensatory/ guarded motion is so common in sports injuries. The assisted scapular motion created with this purple band is perfect for minor rotator cuff injuries and shoulder impingement.