until you just think you can't do any more without hurting yourself
I'm gonna tell you how to do them
Put your arms at a 45 degree angle from your torso
inhale when you're at the top, exhale at the bottom, so you don't forget to breathe
make sure to keep your back straight. Flexing your belly can help with this but try not to flex it too hard or you'll impair your breathing and tire yourself out too quickly
You can keep a steady pace and let yourself spring a little bit off the bottom to help you do more, but don't bounce
I think that's all the important stuff, if you have any problems let me know. And remember to have fun! also please tell me how many you manage to do. I'm hoping for at least 20!!!