You'd be hard-pressed to find more than a handful of people who don't sit for more hours of the day than they move. And when you do something over and over again, your body gets really good at doing it. In fact, your connective tissue—the supportive tissue under your skin designed to support, protect, and stabilize you—helps you sit for long periods of time.
However, connective tissue, a.k.a. fascia, also stores energy, so your muscles can do their job while staying connected and balanced. What science is starting to recognize is that if you sit for long periods of time, fascia loses its supportive, elastic qualities, and muscles can become neurologically inhibited so they don’t contract or release when they need to. This leads to neck and lower-back pain, muscle and ligament strains, and injury. It can even accelerate the aging process.
When we sit for long periods of time, we're siting on the backs of our thighs and on our butts. What most people don’t realize is that 80 percent of your gluteal muscles attach to an important fascial structure called your iliotibial band (IT band) and the other, lower fibers attach to the lateral femur (your big leg bone). When we sit, the upper fibers become compressed and shortened while the lower fibers are lengthened. This can cause everything from hip and lower-back pain to cellulite and sciatica to overall poor posture. Just strengthening your glutes—by doing things like squats, running, and plyometric jumping—only increases your risk of injury as your connective tissue has become dehydrated and the important timing of the gluteal muscles isn’t present.