Compression socks can improve performance, decrease lactic acid buildup and minimize muscle soreness, right? If you’ve been running for longer than a year it’s likely that you heard at least one of these statements regarding compression socks. Some runners will swear that it works and others will say it’s a myth. If compression socks can increase running performance how might they do so, and what does the research say?
Understanding the Claims
Before we get into the knitty gritty of physiology, let’s start with compression socks role in blood flow and venous return. Our heart’s number one job is to pump oxygen-rich blood to our muscles and organs. When we run the demand for oxygenated blood increases so, in order to fill the new requirement, our heart beats faster and we breathe harder. Once our muscles take the oxygen out of the blood and dump in waste products (like lactic acid) our body has to work twice as hard to get the deoxygenated blood back to the lungs and heart to be refueled. Bringing blood back to the heart is more challenging due to gravity, so our body uses our muscles as pumps. Everytime our calfs contract they squeeze the veins in the lower leg, giving the oxygen-poor blood an extra boost. Once the blood finds its way home the whole process starts again.
But what does this have to do with compression socks and performance? Well, the more blood we can send back to the heart the more oxygen-rich blood we can send to our muscles. If a muscle has a higher supply of oxygen it can continually convert that oxygen into energy through the mitochondria. Considering compression socks constantly squeeze the calf, it would make sense to assume that the added pressure would contribute to muscle contraction causing even more blood to be sent back to the heart. The more blood we send back to the heart, the more lactic acid byproduct we are getting rid of. If we can get more oxygen rich blood to our muscles while simultaneously removing lactic acid then running performance should improve! What these statements have in common is “if.”
What do the studies show?
I was able to find multiple studies that pointed towards a clear answer - YES! Compression socks have been shown to increase performance and reduce muscle fatigue during bouts of exercise. In the studies done, they had two trials where runners run without compression socks and then again with compression socks (to put it simply). In every study the experimental group that ran with compression socks did better on the second trial. But why? This is where the studies begin to diverge from popular opinion. One of the biggest factors for increased performance was athlete perception. Preconceived notions of the effectiveness of compression socks may have added a placebo effect which would result in higher performance. Although it may seem logical that lactic acid concentrations were lower in subjects using compression socks, studies found that groups wearing and not wearing the socks had no difference in acid concentrations after a bout of exercise. However, the studies did support and find a significant difference in recovery during bouts of exercise; but it may not be why you think. The constant pressure applied by the compression socks inhibited inflammation. When muscles are damaged during exercise an inflammatory response is created to remove any waste and breakdown muscle to form new, stronger muscle. Therefore, the compression socks were able to hinder inflammation because of the lack of room necessary causing a temporary increase in recovery rate during bouts of exercise. As for any other possible benefits of compression socks (like an increase in venous return) there just isn’t enough data to support a definitive answer.
We may not know exactly why compression socks work, but they do! Their effects on running performance are clearly seen through a multitude of studies. If you’re still skeptical, try them! Maybe you’ll hit a new PR.