Not sure this is me, hips are strong..but maybe someone else? Your achy knees while running may be due to weak hips. Strengthen the hips and running may be enjoyable again...not too mention much smaller hips:) - Good to keep tucked away in case I need it.
Audrina Patridge's Workout consists of 4 moves for a 6-pack: Cat Raise, Cross-Legged Lift, Compound Crunch, and Offset Bridge. Two or three times a week, do one set of 20 reps of each move in order without resting then repeat the entire routine once or twice.