Hi Im training for the london marathon which is 4 weeks away and I've recently been experiencing knee pain during my long runs. The pain is dull and above the knee cap. It gradually gets worse and then I stop to stretch and continue. When I start again I have to slightly adapt my style due to the ache and then I'm able to run normally for a while before having to repeat the whole process again. Last week I managed 19miles and yesterday I got to 14 miles. Has anyone experienced this? How can I treat it to enable me to continue? I brought my trainers from the meet the experts expo in London back in January where I had a gain analysis and was advised on these trainers. With only 4 weeks to go I'm really concerned I'm not going to be able to run. I'm due to do a finally long run next weekend of 21 miles but am concerned if I do it I might make things worse. I've done 5 long runs over 13 miles, 19 being my longest last weekend. Is that enough training to get me through or should I grit my teeth and do my final long run? Any advice would be appreciated.