This week's question has to do with recovery:
How do compression socks work? And do they help protect tendons from overuse injury?

If you've been to an endurance event in the last few years, you might have noticed more and more people wearing socks that go up over their calves. Fortunately the fashion trend of prior decades has not returned (we hope). What you are seeing are athletes wearing compression socks to aid in their recovery. You might also see some athletes wearing these during the race.

Why compression?
The premise behind these socks are that the snug fit actually improves blood flow in your leg muscles. Diabetics, who are especially prone to swelling and circulation issues have been wearing these for years. So why not translate this into the endurance sport industry? The better the blood flow to the muscles, the easier oxygen and nutrients can get in and waste products can get out. And that means a quicker recovery.

In addition to improved recovery, another claim is that compression socks actually improve performance or at least delay the onset of fatigue. You'll likely see athletes wearing compression socks during an event in a longer distance race, such as a half or full ironman distance triathlons and half and full marathons. CEP sites a study using their brand of compression socks that claims 5% faster running times. Another manufacturer, 2XU, provides studies of improved performance as well.

Briefly, an explanation of improved performance would be that the increased blood flow provides more oxygen to the muscles, allowing them to perform better. There seem to be mixed results on this aspect of compression, so to know for sure, you'd probably have to test them yourself.

OK, so if compression socks work on the lower legs, are there compression products for the rest of the body. The answer is yes - many manufacturers have compression garments as shorts, tights, arm sleeves and shirts. And if you are really into compression for recovery, check out the NormaTEC MVP.

Regarding the tendon question, I didn't find a whole lot out there, so if anyone can point me to some references I'd appreciate it. My guess is that since tendons connect the muscles to the bone, if you're improving muscular blood flow, then the tendons will see some benefit as well. But because there is limited blood flow in the tendon/ligament arena (why those injuries take a long time to heal) the bulk of the benefit is to the muscle in its recovery and performance. But happy muscles will probably help make happy tendons.

Note: There are many manufacturers out there of sports related compression garments and I don't endorse a particular brand. I'll name a couple more: Skins is out there and so is Zensah.

Some other links that you might find enjoyable
A more thorough review of some of the research at The Science of Running.
A good discription of how compression socks work.
Fun article by Peter Segal.