The Lactic Acid Myth

Have you ever had that feeling after a hard workout where your muscles felt sore, fatigued, and maybe even painful? Well don’t blame that soreness on lactic acid. Lactic acid has taken a beating over the years due to the belief that this was the source of that post workout pain. Understanding what lactic acid is, the role it plays in exercise, and what the real source of our post exercise soreness is may actually change the way you look at your recovery days.

Lactic Acid or Lactate?

Without getting into the chemistry behind the two, the most important difference is that lactic acid is just that an acid, while lactate is a byproduct of a chemical reaction that occurs in the body during glycolysis. Lactate can also be used as a fuel for muscles, the brain, and heart. Lactate does not build up in the body unless the production of lactate rises above the clearance of lactate, this is called the lactate threshold. Athletes, particularly endurance athletes, will sometimes train to challenge and increase their lactate thresholds in order to compete at higher intensities for a longer period of time, this is called lactate threshold training.

What Causes Muscle Soreness?

Lactate generally leaves the body one hour after training. Therefore it’s pretty clear that this cannot be the problem causing muscle soreness days after our workouts. This also means lactic acid flushes or lactate recovery techniques recommended days after training are pretty much useless. So what is the real cause of muscle soreness? Researchers believe that small tears, and damage to muscle fibers leading to inflammation and swelling are the real culprit. This post workout soreness has been termed Delayed Onset Muscle Soreness or DOMS for short.

What can you do to help with DOMS?

The first and most effective way to deal with DOMS is to have an appropriate exercise progression. A personal trainer or other exercise professional should create a program that will challenge you, but not make you feel like you can move for days after the workout. Eccentric exercises have also been shown to cause DOMS more often than concentric or isometric exercises. This does not mean to ignore eccentric training altogether, just limit the volume of eccentric exercises you perform in each workout. Generally DOMS will relieve itself within 72 hours, but if you are looking to participate in an active recovery there are a few things you can do. Soft tissue mobilization like our hawk grips treatment, light activity following your workout or on a recovery day and proper nutrition can be somewhat helpful. Stretching and icing have not shown to make any difference in recovery times following DOMS.

Stop Blaming Lactate

So the big take home message here is that lactate or lactic acid is not the source of DOMS. DOMS is caused by small tears that occur within the muscle during hard training. Stretching and icing will most likely have no impact in your recovery time, and be sure not to let anyone sell you any lactate clearance treatments days following training because your elevated levels of blood lactate will have cleared within an hour following training. If you do want to accelerate the recovery process after DOMS, try some target soft tissue mobilization, an active recovery and make sure you refuel your body with the right nutrition.

About the author:

Dr. Kevin Prue PT, DPT, CSCS is a graduate of Duke University’s Doctor of Physical Therapy Program. He is the president and director of Prue Physical Therapy & Sports Performance (www.pruept.com) located in Cary NC. He specializes sports and orthopedic physical therapy, sports performance training and injury prevention for youth and recreational athletes.