You probably know where your glutes are. Thanks to your job, you have extensive knowledge of the seated workplace environment. But just because you sit on your glutes when you work doesn't mean your glutes work when you sit. In fact, working your ass off is a phrase which was probably motivated by the detrimental effects of the workplace environment. Sit on those cheeks long enough, and it won't matter which one you turn. You won't find either of them, because sensory motor amnesia has put them on a permanent lunch break.
Sensory motor amnesia is a term first used by Vladir Janda to describe a muscle which no longer works. Via either pain or disuse, the muscle has "forgotten" how to function. And the longer any muscle is turned off, the harder it can be to turn back on. But before you get your panties in a wad--oh, wait...you can't since your butt is purely hypothetical at this point. So maybe you won't even be phased to hear that your ass is likely not the only part of your body on sabbatical.
That's right. Two other areas commonly prone to sensory motor amnesia are the abdominals and the scapular adductors. Now, if you don't have a Budweiser tumor, I'm sure you're at least familiar with the look. It's about as ubiquitous as it is unattractive. And while highly correlated with alcohol consumption, even teetotalers can be prone to this look as there are many sources for dysfunction here.
Scapular adductors on the other hand, may be testing the limits of your anatomical knowledge. These are a group of muscles which, as the name implies, adduct your scapulae. When you stand up straight, lift your chest, and externally rotate your shoulders, these are some of the muscles responsible for that action. Unfortunately, most people don't stand up straight, lift their chests, or externally rotate their shoulders. Thus, the majority of folks, even if they can locate these muscles, will find that they're inhibited.
How do we bring these three key areas of the body back on line? Well, the first step is simply to touch them. Palpating a muscle helps you become aware of that muscle. When I'm working with a client who cannot fire a particular muscle, one of my strategies is to continually tap the inhibited muscle while they perform a movement involving that muscle. If the client actually gains awareness quicker than I annoy the absolute crap out of them, then the potential to fire that muscle increases exponentially--especially if the muscle is responsible for a right cross to my nose. And once the client can activate a muscle, then we can finally work the muscle. It's kinda like the brain in that respect: use it so we don't lose it.
For additional insight into the cause of as well as the cure for sensory motor amnesia, read the following post: http://triumphtraining.com/blogs/blog/6364218-365-ways-193-why-your-lower-abs-are-absent