Okay, pushups are the stereotypical home workout exercise. Unless you are already fit, they SUCK.
There is a way to do this exercise, at home, and succeed at building up to doing pushups as well as a Marine fresh out of boot camp.
There is already a link to doing 100 pushups in six weeks. I tried this and stalled at the end of the second week. I became discouraged and didn't continue with it. The frustrating part is that I want to be able to do this. I have found a way to do it which cannot fail.
If you take a look at the 100 pushups in six weeks program, it makes sense. You figure out what you are capable of now, work at that level, and gradually increase the workload. If you are struggling with doing just a few pushups with good form, then increasing the workload before you can do a few with good form is not going to work.
My solution to this is simple.
I don't even like the knees down type of pushup. They hurt my knees too much. There is a better way than dropping your knees to the floor.
Do your pushups while leaning against some stairs.
This transfers weight to your feet, giving you less weight to push up against. Give it a try. Stand facing some stairs. Place your feet close to the bottom stair. Lean forward and place your hands on a stair so that you can comfortably do a push up. Now try a few.
See? Much easier than a proper push up or an knees down push up.
If that is too easy for you, move your feet back and try pushing up on the next stair down.
What you now have is a way to do the push up exercise, with decreased resistance. The trade off with this modification is that the angle changes which part of the chest muscle is being exercised. For those of you who know what a declined press is, this is what you are doing. It still works your chest as a whole, just focuses on the lower part of the muscle.
While playing with this idea I tried doing a pyramid type cycle using the stairs. I started on the highest stair that was comfortable and did push ups till I was feeling tired (not till failure). After resting for a minute I went back and did the same thing on the next stair down. I kept doing this until I was doing a proper pushup on the floor. I continued on and did a few with my hands on the floor and my feet on the stairs (harder than normal push ups). When I reached the point that I couldn't even do one pushup I started going back to easier push ups. I brought my feet down a step, then another...did a few normal push ups...then started doing the easier push ups with my hands on the stairs.
I learned a few things by doing this. First, it is much nicer to do push ups with good form and less resistance. Second, being able to set the resistance higher and lower allows me to do more exercise than by just doing normal push ups. Finally, doing that pyramid circuit without being in shape will destroy your muscles. I couldn't move my arms for a few days afterward, I couldn't even do a single push up.
My plan to move forward from this is to do the 100 pushups in six weeks program using a lower resistance push up on the stairs. I figure that if I can complete the program at a lower resistance, I can do it again with more resistance and build up to doing it with normal push ups.
Some extra ideas to help with the push ups:
Strengthen your arms by doing bicep and tricep curls. Use a heavy object if you don't have barbells or dumbbells, a gallon milk jug full of sand or water will do in a pinch.
Bent over rows with a similar weight will help build up your back muscles too.
These muscle groups help perform the push up exercise. Building strength in these other muscles will help you achieve your push up goal.
These muscles, and others, can be strengthened using the shovelglove exercises described here. I personally love the shovelglove exercises because they are made for slackers like me. If you don't know about shovelglove I will share my thoughts about it now. Shovelglove allows you to exercise your whole body with the least amount of work and hassle. The hardest part of shovelglove is picking up a sledgehammer. If you can pickup and hold a sledgehammer, you can get fitter and stronger without a lot of extra effort. Perfect for slackers. You can even watch the TV while you do it.