I have been in training for the FLM and so far no real problems covering up to 18 miles. Yesterday, however, I had to start walking after about 12-13 miles, because of knee pain, outside of left knee to be precise. This is a new problem, could it be related to a weeks ski-ing last week? I am very worried about carrying on with training and the taking part in the FLM itself! Any advice gratefully received!