After the training we usually follow this set-scheme before we start the cooling down:

20 with arms under your shoulders
5 to 10 sec. rest
20 with your arms wide
5 to 10 sec. rest
15 with arms under your shoulders
5 to 10 sec. rest
15 with your arms wide
5 to 10 sec. rest
10 with arms under your shoulders
5 to 10 sec. rest
10 with your arms wide
5 to 10 sec. rest
"and last but not least, for the real strong men and woman" (thus says our trainer)
5 with your hands opun one another underneaht your chest, going as low as possible, trying to touch your hands with your chest.
(Sometimes in stead of that, we do 5 on the knockels.)

For every set counts: do as many as you can as long as you can keep your back straight (your back may never become hollow!!! that's really bad)
I started with trying to do the scheme on my knees, and could hardly follow up, but in about 3 months i can do it without to much effort.