I've seen marathoners with six packs as they are visible because their body fat is very low. However, they are not solid as what you said.
I am a marathoner myself (but no six pack la ) and I am finding a hard time to bulk up to get those so that they look nicer.

Just one question, is it really possible to focus on bulking and doing cardio exercise frequently at the same time(training for upcoming marathons)?

As far as I know marathons and bodybuilding do not go the same way.

I had been reducing my runs so far and focus more on my diet.

This post has been edited by Omega Z: Jan 9 2014, 10:16 PM