What does foam rolling actually “do”?

Foam rollers. Massage roller sticks. Lacrosse balls. Voodoo floss. These are all recovery/mobility/pain-relief tools used by everybody from desk workers, to a typical gym-goer desk worker to even elite professional athletes.

If you’re reading this article you’re probably using one (or all) of these tools. But why did you start using the tool(s)? Most likely, it’s because somebody told you to use it. Maybe it was our clinic, or a trainer, or an online “guru”.

But what is the purpose of these? How do they work? What does the research say? (Note: we’re just going to use the term foam rolling, but the same information applies to any type of “self-myofascial release”).

Does foam rolling break up scar tissue?

Let’s start with this idea. Most people believe that when they foam roll their IT bands, use a lacrosse ball on their plantar fascia, or Voodoo floss their knees that they are “breaking up scar tissue”. The idea is that by compressing the tissue and rolling and moving around, small adhesions can be broken up which leads to decreased pain and improved mobility. This idea is 100% false.

In other words, foam rolling DOES NOT break up scar tissue.

How do we know this? A very old study actually looked at the amount of force required to “break up scar tissue”. That number was 10,000 -30,000 psi (lbs per square inch) (1). Unless you’re foam rolling with an elephant standing on you, you aren’t applying enough force to break up scar tissue.

If you used to believe this idea, don’t feel bad. I also used to believe it!

Does it rolling lengthen muscles or tissues?

Nope. Another big swing and a miss here.

Again, a study has been done to look at the amount of force required to lengthen several types of tissue. To lengthen the iliotibial band by only 1%, a force of 2040 pounds would be required! A force of 1879 pounds would be needed to lengthen the plantar fascia by the same 1%! (2) These are some of the toughest tissues of the body and are often the most targeted with foam rolling or lacrosse balls. If you’re producing this amount of force on the tissues, you are also most likely ripping your skin apart at the same time. All for a 1% change.

Is foam rolling beneficial?

At this point, you might be wondering if it is even beneficial to foam roll. You can’t break up scar tissue and you can’t lengthen any tissue, so what’s the point?

Despite not being able to physically change tissue, there are positive benefits from foam rolling. Let’s take a look at these benefits. (3,4,5)

1. Foam rolling increases blood flow: this is great for chronically injured areas or for muscles that we don’t use a lot (i.e. posterior hip and glute muscles)
2. Foam rolling decreases post-workout soreness: Tough workout? Roll it out, baby!
3. Foam rolling increases range of motion (short-term): Need a little extra mobility before a workout or before your home exercises? Add a foam roller to your pre-workout routine.
4. Reduces muscle pain perception (short-term): While this change is short term, proper therapy/exercises can then be used to produce long term changes.

How does foam rolling work?

So if we can get these benefits from foam rolling, what is the mechanism by which it works? Caution: we’re about to get a little nerdy here. Feel free to skip to the next section if you’re not into nerdy stuff.

Basically, using a foam roller or a lacrosse ball or those vibrating therapy “guns” all work by stimulating tiny little organs in our tissues. These organs are called mechanoreceptors. Each receptor type in our body can be stimulated in different ways. Let’s take a look at some of the most common mechanoreceptors in the body and the changes they can produce when stimulated.

1. Pacinian corpuscles: respond to rapid vibration and changes in pressure.
2. Ruffini endings: respond to deep pressure and rapid vibration
3. Merkel discs: respond to constant pressure
4. Golgi tendon organs: respond to muscle contraction (not stimulated much with foam rolling)

When these mechanoreceptors are stimulated, they send a signal to the brain. In response, the brain basically tells the stimulated muscle to relax. This is why we get an increased range of motion. Stimulation of some of these receptors also decreases the activity of the sympathetic nervous system (our “flight or fight” response.) This will also lead to decreased muscle tension as well as decreased pain and increased blood flow. The increased blood flow is the main mechanism for decreased post-workout soreness.

Obviously, it’s a lot easier to say “foam rolling breaks up scar tissue” over “foam rolling stimulates receptors in our tissues which provides an altered neurological signal to the brain which results in sensory and neurophysiological changes to the body.” So does it really matter “why” it works? YES!

If we know the mechanism of “why” foam rolling works, we can make the “how” of foam rolling more beneficial and time-efficient.

How should I do it?

Let’s first start with how NOT to foam roll. Based on what we learned, we know that we aren’t breaking up scar tissue. Therefore, there’s NO reason to make foam rolling as painful as possible. Basically, a “good hurt” sensation is all you need to stimulate the deep pressure receptors. Anything more than that and you’re wasting your time and energy. You may also cause your muscles to contract and become tighter. Definitely not what you want.

Getting back to the “how,” we can set up a few simple rules with foam rolling to help guide us.

1. If working on mobility, then work all muscles around that area. For example, if you want improved hip mobility then work the hip flexors, the glutes, hamstrings, quads, and adductors. If a muscle crosses your target joint, hit it with the foam roller.
2. When working on muscles, alternate between deep pressure, light pressure, slow movement, and rapid movements. By differing the technique, we can hit different mechanoreceptors. If you have a thera-gun or vibrating foam rolling, use that too (but don’t use that exclusively, variety is key)
3. If the goal is pain relief, work on the area with various techniques as noted in rule #2. This only decreases pain short term so now is the perfect time to work on corrective exercises.
4. In general, the benefits of foam rolling are small and short term. So don’t foam roll for an hour. Perform small sessions of 5-15 minutes. If you have extra time, you’re probably better off performing specific mobility or stability exercises rather than just doing more foam rolling.

Conclusion

Hopefully, you have learned a thing or two about foam rolling. Now you can be a little more focused on your self-care and have an idea on what you’re trying to accomplish. Feel free to ask any other questions you have!

Jeff Remsburg, DC, MS, DACRB, Cert. MDT

References:
1. Gratz, C. J Bone Joint Surg. 1931
2. J Am Osteopath Assoc. 2008 Aug;108(8):379-90.
3. Int J Sports Phys Ther. 2015 Nov;10(6):827-38.
4. Front Physiol. 2019; 10: 376
5. Aboodarda S., Spence A., Button D. C. (2015). BMC Musculoskelet. Disord. 16:265