This exercise is for any fitness level and works more than one area at a time.  Beginners can start with performing this exercise on their knees and work up to the toe position.   It is a great over all body workout that builds strength and incorporates the core (trunk musculature).  It targets the chest, arms and the abdominals.

• Get in push-position on toes (or knees, if necessary) and hands, so the body forms a straight line from head to heels.
• Do a push-up, then draw your right knee under you and to the left side (aim for your left elbow), so your knee is just a few inches off the floor. 
• Place right foot on the floor and repeat on the other side to complete 1 repetition bringing left knee under you and to the right side (aim for right elbow).
• Begin with 10-15 repetitions each side.
• Work up to 20-30 repetitions.

Tip for Beginners:  Beginners start on knees while performing the push up and work up to as many repetitions you can do with good form.  Then work up to building strength to perform the exercise on your toes.