The purple assistance band is often the perfect band for someone who is still trying to master their first pull up, or working on doing a few consecutive pull-ups. The 50-80lbs of support helps people to go through the motion of doing a full pull up and strengthen those muscles that are needed to do unassisted pull-ups. For those looking to master muscle ups or other more advanced moves the purple band is also great and often offers the assistance needed to do the full motion.
Additionally, the purple band is perfect for heavier resistant training and commonly used to strengthen the legs and back. The purple band is a great part of your workout arsenal no matter what level of fitness level you are at.