Let's say I'm a little too fat to be doing a real push up.
Do you recommend me to push up with my knees supporting my body first and then progress further?
OR
Do you think it's better if I start with the less push ups, (say.. 5.. 10..15.. incremental over days)?
My goals are to increase endurance, strengthen my wrists, forearms, and chest.
Disclaimer: I'm not really fat. No offence to any if they sorta are.
You should do the push as it was designed. While it may be difficult at the start and your rep count may be low it will facilitate proper body position and with time your rep count will increase.
You can try to make 12, with knees support.
Once you can do 12 with knees, then you can do it as usual.
In general, to build muscle, try to reach to 12 reps, and then increase the weight.
Use a plyo box or something similar. So you put your hands on the top edges of the box and do a push up as normal. Use a shorter box to make it more difficult until you can do them off the ground. I feel this is better than knee push ups if you need to scale the movement since to me they feel closer to real pushups.
Doing good controlled pushups from the knees is definitely a great way to start, because the use of muscles in the arm, shoulder, chest and core are almost identical to those used in real pushups. However, I would deviate from the other comments by adding that, as soon as you can do even one real pushup, start with that, then complete your set on the knees. If you keep up a good program doing this 2-3 times a week, soon you will be doing multiple strict pushups and you can build from there.
I don't agree with JoaquinG that you need to start adding weight once you can do 12 reps -- for me the benefit of pushups is that they are a very simple no-equipment bodyweight exercise that can be done anywhere, anytime, and building up to 20, 40, 60 reps is fine and continues to pay off in both endurance and appearance.
