I can certainly appreciate the concern with protecting the joints but don't forget normal exercise is good for building good muscle tone. The pup will let you know when she is tired...mine would just plop
I loved being outside when my boy was a pup. I used things in our yard to build little obstacle courses. He was running, climbing, balancing, etc. as he grew I was mindful of not over doing it. I have stayed from playing games like frisbee because I don't like how dogs land when they catch.