Rolling is beneficial before and after your workout, though people have different preferences on when to roll. Foam rolling prior to a workout can help decrease muscle density and allow for a better warm-up. Rolling after a workout can aid in recovery for sore muscles after strenuous exercise. There?s really no wrong time to do the thing ? just make sure you do it! Other benefits of self-myofascial release include:

Improvement in joint range of motion
Ease of muscle soreness and joint stress
Help in maintaining functional muscular length