Track and Field Blogs - Austin Waldrop

I don't think XT will hurt your base, but I would stick to pure running as the best way to boost the aerobic capacity. Gradually / cautiously, and alternate efforts / volume so that you allow your body to adjust to the demands. Keep on building that engine before you go into any hard stuff... and of course, rock those weekly long runs. Research about Arthur Lydiard's theories. You will see how the long-term development of the aerobic capacity is the most important aspect to reaching your true potential. Good Luck!