There's a lot of debate about which muscles are 'core' muscles and which exercises you need to do to improve core strength.
Most people think that core muscles are those 'somewhere behind your belly button'. Physiotherapists get people to lie on their back and suck their guts in to strengthen those muscles.
Not many people became stronger by sucking their guts in.
My definition of core muscles is any muscle attached to the pelvis or the spine.
Withjout complicating the sipple you ought to be able to look after your core strength by regularly doing these four exercises:
1. Situps of any type.
2. Pressups definitely. Pressups are plank in motion - the best predictor of risk of lower back pain.
3. Squats - don't forget that core muscles are any muscles attached to the pelvis or spine. Just get a piece of wood an inch or so thick, place it under your heels and start squatting. Make sure your backside goes below your knees.
4. Superman - don't forget the muscles on the 'back side' of the body.
If everyone could do 40 situps, 40 pressups and 40 squats doctors, physios and chiros would be sitting around twiddling their thumbs.
In the meantime stay tuned, highly tuned, keep strengthening your core muscles and visit http://www.globalbackcare.com for a complete musculo-skeletal health training program.