pain behind my knees while walking extensive miles

Question
Hi. I have been training since June for the 3 Day Breast Cancer Walk in San Diego which is in about three weeks. I am with a training group, and we are up to about 40-45 miles a week. In the past couple of weeks, I am experiencing pain behind my knees ( soreness while walking) and then stiffness once I have stopped and am sitting for awhile. Initially, this just occured on one leg, and now it is impacting the other. I did lay off the walking for about 4-5 days which helped the knee pain, but with the 3 day approaching, I want to make sure I don't hurt myself more, and yet still need to train. I appreciate any thoughts or suggestions you might have.
Thanks,

Answer
Did you increase your mileage too quickly? Do you stretch properly after you walk? Have you been trying to walk too fast? Are you wearing good fitting, quality running shoes? Just a few questions that might relate to the problem, but you can't go back and change it now. When I first started racewalking, I developed some minor pain behind the knee from throwing my leg out in front to try to straighten my knee (a requirement for racewalking). It went away as I got in better shape.

The truth is that I can't give medical advice, and that may be what you need. I suggest you see a sports-oriented chiropractor for some help.

The worst time to get an injury is close to your planned event. You probably have done enough training already to get you through the event, so healing the injury should take priority. I know you don't want to hear that, but by properly taking care of the injury you would maximize your chances of succeeding in your walk.