A foam roller is a cylindrical piece of equipment used for myofascial release, which means it helps to loosen and relax tight muscles and connective tissues. It's commonly used in physical therapy or by athletes as part of their warm-up routine before exercise. The user lies on the roller and uses their body weight to apply pressure onto different parts of the roller, which in turn applies pressure onto specific muscle groups. This process helps to break up adhesions and knots within the muscles, promoting better flexibility and reducing pain or discomfort. Foam rollers come in various sizes and densities depending on the user's needs and preferences.