How it works: Squeezing blood vessels causes them to open forcefully, which allows more blood and oxygen into the compressed muscle and helps shunt waste. This in-with-the-good-out-with-the-bad increases the working muscles’ capacity to produce energy and allows the wearer to run faster.
Does it really happen?
Research conducted by the University of Newcastle found that lower body compression garments increase blood flow and reduce heart rate during high-intensity endurance running, supporting the theory that compression socks should improve performance. But that same study didn’t find that compression clothing actually made runners faster. And other researchers have also found that compression socks don’t improve 10K running performance. Three things could cause this contradiction: The original finding could be wrong, the runners’ performance might be improved by an amount too small for the study to find significant or the weight of the socks could counteract their physiological benefit. It sounds crazy, but carrying the socks—they weigh roughly three ounces—hampers performance. For some perspective, three ounces is the same weight difference between Asics’ supportive, gel-cushioned Kayano trainers and their lightweight road-racing shoe, the Speedstar. Three ounces is not trivial.