<human>: I adopted my GSD, Max, about three months ago. The rescue is unsure of his exact age, but he's around 14-15 months now. He's quite energetic and I live in an apartment, so I walk him 30 minutes in the morning and 30 minutes at night every day in addition to taking him to the dog park almost every day where he runs happily with the other dogs for about an hour. He seems tired after this, but not exhausted--still excited for his evening walk, but calm and content to sleep or chew a bone. He is a fairly polite leash walker and improves daily. We use an EasyWalk harness.
I used to be a bit of a runner before I got him, and I want to run again, but I'm concerned that I'll damage his joints. If he's walking an hour and running/playing for an hour each day, would it be a strenuous addition for me to run with him maybe 3x a week for 30 minutes in place of his dog park time or his evening walk? Should I wait until he's 18 months - 2 years old? I run pretty slowly, about 10 min/mile. If I'm running on concrete (or I guess I could find gravel/pine straw/maybe grass), will 30 min of jogging be too much at this point?

Sorry for the wall of text--I've read a lot about this, but the articles all say things like "don't push it, try going for a walk first with your puppy." Since we already walk a lot and he runs on grass and mulch at the dog park, I want to get a sense of how different concrete would be for him. I would LOVE for our evening walk to be a run instead.

Condense the text into a few key points
<bot>: Doggit, how have you incorporated running into your dogs' life and do you have any tips for starting to run with a 14 month old GSD?