Hi Ed, thank you for the warm welcome. Regarding the 35 mint 10k plan, I'd like to know your view and advice. Could the 400s begin changed for 12,16x?and the 1k reps being changed for 10x1k?rest times remaining the same.one last question,reaching those speeds is not a problem for me. The problem is maintain that speed for the all race. I only manage for abaut 15 mint. Its a lack of endurance or a lactic acid problem? I'd love to know your advice and opinion.probably will be more fellow runners out there with the same issue as me. Thank you so much.