What is it? Is it any good?
Foam rolling is thought to improve muscular performance and flexibility as well as to alleviate muscle fatigue and soreness. For this reason, foam rolling has become a popular intervention in all kinds of sport settings used to increase the efficiency of training or competition preparation as well as to speed post-exercise recovery.
For a detailed look at the effects of foam rolling see a meta-analysis by Wiewelhove et. al. A Meta-Analysis of the Effects of Foam Rolling on Performance and Recovery