Dok-torr, thanks for mentioning core strength and the plank exercise. Another interesting detail is that "core" stretches all around the trunk, so strenghthening the sides will add to core strength. You can do the plank while lying on your side, either by bracing with your thigh and knee bent (easier), or with straight legs and bracing from the feet (harder).

This is one of my pet topics having gone through physical therapy for my back recently. The idea of using my abs to get my weight off my hands seems impossible at the moment, but that's because I'm still getting stronger.