I like to work out every day as part of battle against aging and the effects of sitting statically in my office chair all day. One part of that daily regiment is pushups and sit ups (or crunches). I hate doing the later. Sit ups are just plain uncomfortable and unnatural, it seems, for me to do. Because of this I am always experimenting with of working the core muscles _without_ doing sit ups.
Here is one that I really like that does an awesome job of working the abs, lower back _and_ pecs all at the same time. It’s a variation of the pushup witch is ideal for me as it kills multiple muscle groups at the same time. Here is what you do:
* lay face down on the floor
* place your hands on the floor near your shoulders with your fingers pointed towards your head
* spread your legs apart so that your feet are more than shoulder width apart or as far as comfortable
* prop yourself up onto your toes and push up with your arms
* once at the top, raise one leg off the floor, keeping it spread out as far as possible
* watch your balance and attempt to do 10 pushups with your leg raised
* once you’ve completed 10, put that leg down and lift the other one for another 10 pushups
* after those 10, put both feet on the floor, legs still spread and continue doing as many pushups as you can (try to at least make it to 10)
* once you’ve finished all 30 (or collapsed), rest for 1 1/2 minutes and start again
* try to do at least 3 sets of these 30 reps
When you’ve done this you will realize just how much this is working your core. Enjoy and work out safely!