We have a similar thread ATM:
tendonitis help! /practice routine!
http://www.drummerworld.com/forums/s...ad.php?t=84539
You might find some useful info there additionally.
You should experiment and find the right balance four your body to push for some time (get in the 'red' area) but then to relax and rest so your body can adjust. It's nothing you can write down and stick to for months and years. With more practice you will be able to crank up your practice, but you'll still need some rest in-between.
I wouldn't recommend to go on when having sore muscles. You COULD go on when you feel that, say, half of the fatigue has gone, but be careful and don't play at your maximum. I'm starting at slow tempos after fatigue. As my muscles are refreshing I would gradually increase my practice/speed/intensity. It's a permanent process of adjustment. Sometimes I would hit softer/practice at reduced dynamics to still practice the motions, but with less power and usually at lower tempo also. In some cases even this/going on with reduced steam doesn't make sense so I would rest.
What you can do is make sure you're warming up properly. Good nutrition & enough amount of sleep is another aspect - with good nutrition and good rest your body will replenish faster.