I'd watch her jumping in the air and slamming down if that's going on with the ball chasing. Running itself, on grass wouldn't concern me as much.
Also, without x-rays you can't tell anything.
I give my dogs the joint mix of
Nutri-Pet Research Nupro Joint Supplement for Dogs, 5-Pound
Joint and Immunity Support | Dog Vitamin Supplements Dog Vitamins Arthritis Dogs Treatments
Alot of pet stores have it and you can also get it online. Make sure it's the one with the silver label, that's the joint mix. It's a brown powder you just sprinkle over the dogs food and then add water to gravy it. My dogs LOVE it!
MACH3 Bretta Lee Wildhaus MXG MJG MXF MFB TQX HIT CGC TC
Glory B Wildhaus AX, AXJ, XF
"Behind every great man is a woman rolling her eyes." - Jim Carrey