[Please note: a simpler article on this topic, written for clients, can be found here.]
Lactic acid has been blamed for delayed onset muscle soreness (DOMS) for decades. Physiologists once believed this to be true. However, it has been known at least since the 1960s that lactic acid is not responsible for DOMS.
How did this idea become so popular? Who knows? Just about everyone has heard that lactic acid causes muscle soreness. Somehow, the word got out when it was thought to be true. The later news didn't make it past the physiologists and the myth persists and is perpetuated by massage therapists to this day. I'm on a mission to prepare massage therapists to pass the L.A.T., the Lactic Acid Test.
Lactic acid does not cause soreness and massage does not remove lactic acid. However, massage still makes our muscles feel good!
Massage therapists are fond of saying that massage removes lactic acid from the muscles. We need to get up to date on this particular bit of physiology. Some massage therapists are resistant to accepting what has been known by physiologists for decades. Why? I don't know. It's not like it questions everything we've been doing and will put us out of business. Clients don't walk in and say, "I've got a lot of lactic acid in my muscles today, can you do something to get rid of it?" Our clients walk in tight and sore and want to feel better. That's all they care about. They don't care by what mechanism it happens, they don't care if it's lactic acid or not. They just want relief. I like understanding as much as I can about how the body works and what I can do to help. Whether the mechanism by which this occurs is a particular chemical or hormone is probably not going to have a great effect on how I practice. I'm not attached to a particular idea about how that happens. If physiologists tell me that the lactic story was incorrect, it will change how I think and how I communicate with my clients, but it probably won't change what I do with my hands. The fact that what I do feels very good still remains.
The role of lactic acid
Exercise does generate the production of lactic acid and it is thought to be responsible for the "burn" felt during intense exercise, though not for the soreness that occurs a day or so later. We now know that it is completely metabolized within about an hour after exercise is stopped. Not only is it pointless to try to speed this process, since the body takes care of it on its own, but one study suggests that massage can actually slow down the metabolism of lactic acid. In addition, lactic acid is actually a source of fuel. So we, as massage therapists, don't need or want to interfere with this process.
There are a number of articles on the internet that explain the Krebs cycle, the role of lactic acid in the Krebs cycle, and how lactic acid is metabolized. My favorite is Lactating Mythers by Keith Eric Grant, Ph.D. Check it out. And next time you hand your client a glass of water after a massage, skip the speech about "flushing out lactic acid." Just consider it a nice gesture to end the massage.
Okay, everyone should now be able to pass the L.A.T. There's only one question on this test:
"Massage gets rid of lactic acid - True or False?"
If you answered "False," congratulations! You pass the Lactic Acid Test.
Encourage your friends to take the L.A.T.
And now please, can we stop talking about lactic acid?