Why do you need strong abs?

Muscles originate on one side of a joint and then attach on the other side of the joint. When a muscle contracts, it pulls on the bones to bend the joint it crosses. Muscles on one side pull a joint one way, muscles on the other side pull a joint the other way. When muscles on both sides of a joint pull at the same time, with the same amount of force, you don't move. The muscles are working and contracting, but neither is moving anything. This kind of muscle contraction is called "isometric," which means "same measure." Your back and abdominal muscles need to work isometrically to hold you in a healthy posture. If you have no abdominal strength you can't control your back from arching backwards and putting too much pressure on your lower back. If you have significantly more abdominal strength than back strength, you can develop a hunched posture. Stomach crunches can promote poor posture. When you do crunches you develop your ability to curl your torso forward. If you do crunches, also do lumbar extension exercises that balance the supporting muscles for your torso. Good ab exercises are isometric. An example is doing push-ups, or just holding the push-up position. Be sure not to droop in the middle like an old horse. Use your abs to fix your posture. Don't stick out your butt.