Well, sort of. You see, I am a runner. I have running goals. But without training partners or daily external support (like a team) I only lasted a year and a half post college. Additionally, training for a marathon takes so much effort that it left me a little worn out mentally and emotionally as well as physically.
So I found the bicycle and I've been riding hundreds of miles per week, because of course the most important factor in training for the marathon is aerobic endurance, which can be had a little on the bike. Also, I'm running a few workouts and runs every week because that sort of measured intensity is hard to come by on the bike without a power meter. Which is to say, I'm doing the 1-2 workouts I need to run and then a whole lot on the bike. When I get back to running full swing I guarantee personal records at 5k and the halfmarathon and hopefully the 10k.
I used to think workouts during the building phase was ridiculous, now I understand you have to be doing workouts 10+ months a year, even if they are as light as 10x100 meter strides or 3xmile at 10k or slower pace. While aerobic endurance is the most important strength and heart pump capacity and lactate threshold can not be ignored until three months before the final race. They are not the main component, but vital none the less.