The constant compression and muscle underuse of prolonged sitting causes glutes to atrophy and become less effective. When they don’t do their job, other muscles take over, changing how joints work. Not good. Even if your butt isn’t sagging and flat from muscle atrophy, it might be in trouble if you have problems getting out of a chair, squatting or going down stairs. Poor posture is another sign, and so is lower back and knee pain.

Countless exercise programs have been launched in pursuit of that perfect curve, but a terrific butt is about a lot more than looking great in a pair of jeans. It’s not vanity; it’s health.
The muscles of the butt, the gluteus maximus, the gluteus medius and the gluteus minimus, comprise the largest muscle group in the body. They stabilize and rotate the hips, supporting most of the body’s weight-bearing activities. Ideally. “But all muscles can atrophy,” said exercise science graduate Dami Dulaney. “It’s definitely use them or lose them.” Many of us spend the majority of our workday sitting — at a desk, in a car, in front of that computer. Our bank accounts may benefit, but our butts do not.
“Constant sitting shortens hamstrings, and you can’t fully extend your leg,” said Dulaney. “It changes the way you walk, shortening your stride, tilting your pelvis and stressing both knees and lower back. That’s just not how your knees are supposed to work.”
“But I work out!” Sadly, studies have shown that even regular workouts may not be enough to counteract the effects of long-term sitting. “Improving those muscles doesn’t just happen,” said Premiere Health and Fitness trainer Christine Morse. “You have to target them with specific exercises designed to increase blood flow and get them firing. When doing cardio, ramp up the incline to wake up butt muscles.” She recommends squats, leg lifts and donkey kicks — kicking straight backward on hands and knees. “In the gym, target the area with machines like Stairmaster and Butt Blaster.”
“My professor always said, ‘If you can move, you can improve,’” added Dulaney. “Yoga is a great way to start. It stretches out muscles that have been tightened, it brings up the heart rate, and in classes, you have someone to coach you.” Leg raises, side lifts and bridges target the glutes. “For bridges, lie on your back, knees bent. Tense that butt, bring yourself up. You don’t have to get your pelvis very far off the floor to get the benefit. Stair steps — stepping up onto a platform or stair and then back down — work, too. Hold onto something if balance is an issue.”
International studies done to evaluate the effects of prolonged inactivity on the body determined that short-duration, high-load resistance exercises 3 days a week are enough to preserve butt muscles — in a word, squats.

And while muscle function
was still low after two weeks’ exercise, after 90 days it was back to normal.
Three months’ work isn’t that much to ask — when it’s your butt on the line.
Don’t take it sitting down
The unfair need to make a living may have you chained to a desk, but you don’t have to take it sitting down. At least, not all the time. That neat, ergonomically arranged desk with everything right at your fingertips? Efficient, but not the best for your butt. Get up, walk around, hunt down that stapler, stand or pace during phone calls.
“One of the best exercises to fire up those glutes is the reverse kick,” said Premiere Health and Fitness trainer Christine Morse. Hold onto your desk or the wall and kick backward with a bent knee. “Keep your foot flat,” said Morse, “like trying to push a door open with your foot. The higher the foot, the more you work those butt muscles.”
“Try squats. If you have knee or back pain, do wall slides.” Brace your back against the wall, feet out, hip width apart. Slide down the wall to a sitting position, then back up. “Don’t press your knees over your toes,” cautioned Morse. “Keep them over your heels.”
“Hover over your chair a few minutes, maybe while you type one sentence. Anything to increase blood flow to the glutes and get them firing.”

Tricia Dulaney
http://www.tallahassee.com/story/life/wellness/2014/06/24/smart-fitness-tips-getting-glutes-gear/11323277/