I started wearing this as a boxer because too many hooks were putting stress on my rotator cuff. This product has been amazing at how it has helped my shoulder area. I no longer have pain from punching in boxing and elbows in muay thai. I cannot recommend a shoulder ball for martial arts. I took off one star because the product didn't come with any instructions. I had to go online and personally write to the device manufacturer for instructions. Regardless, the device is amazing and the device manufacturer offers amazing support when you reach out to them. I would not recommend this product to people with shoulder problems or people who are active and want to strengthen an important part of their upper body.