I'm sure someone here is an expert. I'm trying to get back in shape, but it's a slow process. In the past I worked my way up to hundreds of push-ups a day. But now it I do 30 I'm sore for three days. I'll push past, of course. But here is where your expertise could be useful! How long should you wait between exercising certain muscle groups? Does the pain matter, or is it just chemicals left over from recovery? Yesterday I also ran a mile, then I played tennis for 45 minutes. How long should I wait to do something like that again? I know you could do these things every day if you're in shape. But I'm not. I'm just getting started.