Let’s say you sit all day, placing your body in an unfavorable position. As a result, your buttocks and your rectus abdominis will get tight, facilitating the backward tilt of the pelvis. Then you get up and go to the gym, where you work on 6-pack abs and “buns of steel”, which will only perpetuate the same pattern. Yes, it is useful to work on your core strength, but abdominal crunches won’t get you there. And yes, it’s important to keep your buttocks strong, but too much “steel” back there – in form of short, tight muscles – will limit the range of motion in your hips and will cause your lower back and your knees to compensate