There was a lengthy article earlier this month in The New York Times on the importance of doing pushups, and how it’s an all-around exercise, responsible for exercising quite a few muscles in a human body.
The push-up is the ultimate barometer of fitness. It tests the whole body, engaging muscle groups in the arms, chest, abdomen, hips and legs. It requires the body to be taut like a plank with toes and palms on the floor. The act of lifting and lowering one’s entire weight is taxing even for the very fit.
Then there’s a blog post on NYT site as well, featuring 93-year-old Jack LaLanne, who still incorporates push-ups into his daily workout. They link to push-up calculator, which says that an average 27-year-old should be able to do 37 push-ups on average, and above 50 in a single session to be considered excellent. Google Video has a few videos on what’s considered a proper push-up.