I don't use foam rolling. I don't teach it. It's mass hysteria.
In weird shortsighted studies(mostly from the National Association of Sports Medicine – a personal training certifying body), foam rollers have been proven to temporarily increase range of motion and strength. But those results were never put up against any real mobility drills nor correct warm up. It's never been compared to the creation of optimal movement. Near as I can tell foam rolling has only been studied against control. So, foam rolling may in fact be slightly better than doing nothing.
The thing that bothers me is why we feel we can somehow conduct soft tissue manipulations upon ourselves. People go to school for years in order to be able to do that.
There are four possible mechanisms by which foam rolling increases range of motion and reduces pain:
One – a concept of self myofascial release.
This is the idea that somehow the fascia of the muscle can be manipulated in order to promote greater range of motion. However, and it might surprise some people to learn this, myofascial release has never been proven to exist on planet earth. I'm not kidding. You can wiki that( https://en.m.wikipedia.org/wiki/Myofascial_release ). So I don't know what it is that people are doing to themselves. But it's probably not self myofascial release. In addition, that fascia is fibrous. It doesn't stretch. Period. Well, it does, but to a maximum of 2% over a lifetime and that's probably not enough to reliably and permanently increase range of motion, mobility or strength.
Two –Golgi tendon organ reflex.
This is a reflex in the brain that temporarily shuts down a muscle that has become in jeopardy. For instance if you extend a muscle too far and then compress it in the wrong place you can temporarily get a massive increase in range of motion ( and also loss of strength), in order to protect itself. Theoretically, this reduces the trigger point activity of a particular muscle and that's how it's effective. However, triggerpoints don't exist (More on that in point 3) Now, I'm not saying for sure that Golgi tendon organ reflex is what is happening when you are foam rolling yourself, but it might be. And if it is, you shouldn't do that. It's a very protective quality of the human physiology and you shouldn't just abuse it just cause there's 50 foam rollers at your gym.
Three – trigger point therapy.
By rolling a piece of foam over parts of your body you can cause that muscle to release through magic portals called triggerpoints. Pressing upon these triggerpoints causes a muscle to relax; assume it's correct length tension with this skeleton; and reduce pain signals to the brain. Sounds lovely! The problem is these things don't exist. All current research shows that triggerpoints don't exist.http://www.ncbi.nlm.nih.gov/m/pubmed/25477053/
Four – you are adding increased distance to a stretch.
By bringing a muscle to its full length and then pressing upon it you're forcing the muscle to be longer than it actually is and this causes a temporary increase in mobility. Problem is all current research points to the fact that you can't really increase range of motion with static stretching. It turns out it was all a neurological procedure all along. What this means is your brain finds a way to tell a muscle what length to assume, and then that length becomes more plastic. You can increase or decrease range of motion. Just not with static stretching and foam rolling. Not permanently.
If you were to just stop and think about it, if you brought a muscle to length, it would become quite tonic. Then, if you were to add a device to that, doesn't that seem like an injury risk?
Well it is. That's been studied too(Scand J Med Sci Sports. 2010 Aug;20(4):580-7. Iliotibial band syndrome: an examination of the evidence behind a number of treatment options). It's up on the page wall.