I have a 5-month old German Shepherd puppy, and I've heard that it's
not good to exercise him too strenuously as it could be bad for his
hips. What I'm wondering is, how strenuous is "too strenuous?" On our
30-minute daily walks, we do run in short spurts---anywhere from 15
seconds to a minute, and no more than 12 such spurts during our walk.

Is this too much running for my dog at this age? Also, at what age
will it be safe for us to run long distances?

Thanks.