We use Nature's Bounty Absorbable Calcium plus Vitamin D3
I'm not sure how these exercises will effect your knee, but some ideas:Walking lunges (for more resistance, add weight OR do lunges up hill)Jumping lungesBox jumpsOne leg step upsTimed stationary wall squats (while squeezing medicine ball with knees)TRX lungesTRX one leg squatsHill SprintsTire FlipsTire HopsLadder drillsIf you need to see exercises, let me know and I'll post a vid.
God, I have *GOOD* knees (knock on wood) and even I cringe from one leg exercises. Honestly... anyone else like this? Ha, *ZERO* interest for me in one leg squats, lunges, etc.!