"Well, I certainly applaud anyone wanting to do a hundred pushups, but take it from this old gym rat, I've spent my entire adult life in the gym, and a program like this one can do more harm than good.
If you only train one part of your body (and that's all a single exercise like pushups is going to do for you), you're setting yourself up for injuries down the road. I've seen it a hundred times.
It's like putting a powerful engine in a stock Toyota Tercel. What will you accomplish? You'll blow out the drive train, the clutch, the transmission, etc., because those factory parts aren't designed to handle the power of an engine much more powerful than the factory installed engine.
Push-ups basically only train the chest muscles and to some extent, the triceps. What you really want to do is train your entire body, all the major muscle groups (chest, back, abdomen, legs, shoulders and arms) at the same time, over the course of a workout. And don't forget your cardiovascular work!
I'm proud of you guys wanting to do this. Three cheers! Falling in love with exercise, eating right, etc., is one of the greatest things you can do for yourself. And you WILL fall in love with it if you can just force yourself to stick with it a year or two and experience the amazing progress you'll make.
But do it right, okay?
My advice, find a good gym, with qualified trainers who will design your programs for you (especially in the beginning, until you get the hang of it yourself) and guide you in your quest for physical fitness. Thirty to 45 minutes a day, three days a week, is all you'll ever need to do (I refuse to believe anyone is so busy that he or she cannot make time for that, especially considering how important it is).
And don't worry about being embarrassed or not being in shape the first time you walk into the gym. You have to start somewhere and almost every one of us were there ourselves at one time. So no one will say anything to you and very, very quickly you will progress way beyond that stage anyway.
Now get out there and do it! :-)"