I have been trying hard to adopt the Primal Lifestyle and I love it. I especially LOVE sprinting and lifting heavy things. I have developed knee pain (mainly walking down stairs and after sitting - although it does hurt a little to run) and went to an ortho guy to make sure I'm not hurting my knees. He explained my knees look good but it appears the problem is over-developed quads and under-developed hamstring muscles. Did this happen to Grok? Other Grokettes? Any suggestions on a good balancing exercise/plan for me? Thank you!