what's your preferred method for getting in better shape for hiking?

I've been doing quite a bit more cardio this year than last, but i feel my hiking condition has not improved much as a result. I've been running 5k and doing 100floors on the stair masters at gym couple times a week but still experiencing sore and burning quads after a while causing me to stop and wait for the lactic acid to go away.

Last year i didn't do ANY cardio at all and i felt the same way doing more or less the same hikes .... and worst of all, my condition didn't improve much as the hiking season went on. I guess I did about 2 hikes a month last year and about the same this year in addition to the cardio training

What do you guys do to get in better shape? Do you just hike more than me?