Exersicing for Stronger Core
That's right. Training your core means not moving a muscle in most cases. Why is that? Because your core muscles are there to prevent your body from potentially damaging movements in the mid section. This way the core muscles protect your spine from injury.
Basically while every other muscle group in the body has to be trained with movements, the core can get strengthened with exercises like plank on a swiss ball, swiss ball knee tuck, glute-bridge.
Fact is stronger core muscles can lower with 30 percent the lower back pain. And adding swiss ball to training the core (for not moving core exercises) can make you four times more stable in the mid section - necessary not only for avoiding lower back problems, but also for improved body posture. The conclusion - less chances for injury and pain and more aesthetic look.