Foam rolling: That hurts-so-good muscle recovery must-do that you either hate to love or love to hate. No matter how you feel about it, you've probably turned to a foam roller a time or two to relieve some nagging muscle pain that just won't go away.

But, other than the fact that your trainer, doctor or even just your friend recommended that you try it, how much do you really know about foam rolling?

"Foam rolling is a type of soft tissue work that's more formally called myofascial release, and it can help alleviate muscle pain and tension caused by adhesions that can form between your muscle and your fascia," says Leanne Wonesh, athletic trainer at Houston Methodist. "Often, these adhesions, called myofascial adhesion, are a large contributing factor to painful muscle knots."

You likely have a few questions about that dense roll of foam you so often turn to when in pain, and Wonesh is here to demystify the basics behind foam rolling.

Why foam rolling works

Before addressing why foam rolling works, we first need to talk about why myofascial adhesion even happens in the first place.

"Your fascia is a layer of tissue that surrounds your muscles, separating them from your other organs. As you move, your muscles should ideally glide smoothly underneath your fascia," explains Wonesh. "But, in the space between your muscle (myo) and your fascia, myofascial adhesions can form — causing the muscle to get stuck during the gliding process, leading to muscle knots."

Wonesh says adhesion formation is a natural part of the muscle-building process.

"Any time you're exercising, whether you're strength training or doing cardio, you're going to have a little muscle breakdown. Not only is this normal, but it's what you want to happen since it's one of the early steps in the muscle-building process," explains Wonesh. "While repairing this breakdown, new collagen fibers are used to lay down new muscle. These newer collagen fibers are more disorganized and pliable than your established muscle, and their tangly nature is what can lead to the formation of myofascial adhesions."

Wonesh says foam rolling works to help ensure that these newer, messier collagen fibers lay down flat and in parallel with your existing muscle — reducing the chance of myofascial adhesions forming as you build new muscle.

When and how to foam roll

Maybe foam rolling is part of your weekly workout routine. Or, maybe you only foam roll when you start to feel that nagging muscle pain flare back up. But, even when you do finally get around to foam rolling, are you doing it correctly?

"Since foam rolling can help prevent myofascial adhesions from forming as you build new muscle, I recommend that you foam roll at the end of any workout," says Wonesh. "It's also great for recovery, so I highly recommend foam rolling the day after a heavy workout as well."

As far as how to foam roll, Wonesh offers the following tips:

• Use your foam roller right after your workout — before stretching.
• Be sure to foam roll the muscle groups you used during your workout, as well as the ones above and below these muscle groups.
• Foam roll each muscle group for about one minute, making sure not to exceed two minutes on a particular muscle group.
• As you're foam rolling, make sure the muscle you're targeting is extended and in a stretch.
• Your pace while foam rolling matters less than making sure you're rolling through the entire muscle.

"For instance, after a lot of jumping and squatting, your glutes, quads and hamstrings likely got a pretty good workout," says Wonesh. "In this case, you'll want to be sure you're foam rolling each of these muscles for about a minute, but you'll also want to roll your lower back and your calves as well.

Wonesh also recommends making sure that you're stretching through the muscle group you're foam rolling. For example, if you're foam rolling your calf, be sure your toe is pointed and leg extended.

If you're unusually sore the day after foam rolling, you may have foam rolled too long or too aggressively. Make sure you aren't foam rolling a particular muscle group longer than two minutes, which may mean setting a timer to help keep you from overdoing it.

How to pick a foam roller

When looking for a foam roller, especially if you're shopping online, you'll very quickly realize that there are a lot of choices. And these options vary by price, foam density and surface texture.

"When you buy a cheap foam roller, you're probably just getting a roll of foam — which will be too soft and have too much give under the weight of your body," Wonesh warns. "You want to choose a foam roller with a hard plastic inner cylinder and a thick layer of dense foam on the outside. A well-made, effective foam roller shouldn't give too much, even with your entire body weight on top of it."

As for those foam rollers that add "deep tissue massage" into their name and look like they're sure to bring added pain to your next foam-rolling session, Wonesh says that these are specialty foam rollers that also aid in trigger-point release.

"Foam rollers that have ridges or knobs on the surface are multipurpose. They can be used for myofascial release as you roll through a muscle group, but they can also be used for trigger-point release if you find a knot while foam rolling," explains Wonesh. "By adding pressure to the knot via the roller's knobs or ridges, you can help loosen it. Just be sure to keep it under 30 seconds."

At the end of the day, Wonesh says the key to making your foam-rolling sessions successful is to choose a foam roller that's effective and use it regularly.

"Invest in a good foam roller," Wonesh recommends. "And then be sure to make foam rolling a regular part of your post-workout routine."