Running

Why is it so long between my "great" runs?  You know the kind that make you feel like you really could be an Olympic marathoner, as opposed to just a middle aged women of moderate fitness with mildly aging joints. Most days I'm out there slogging along and either my lungs are aching and I'm wondering when I'll ever be able to breath again, or my legs are about to give out and fail me completely, and I'm pushing and pushing myself just to finished my prescribed length of run.  Then one day, wham, after a few minutes of running everything clicks and half way through my run I'm feeling like I can run forever, like I could truly conquer the world just by running over it.  The air feels great and the music is pumping in my ears (yes, I run with my ipod, always) and I'm truly getting high.  With each step I'm higher and higher.  In my mind I'm a cheetah, really, or maybe I'm Secretariat, or a Kenyan pounding across the dessert with no end in sight, or Wonder Woman. I just want to keep running.  My breathing is smooth and I barely even notice my legs are there.  I just go and go and run and run and run. I want to savor every bit of it for as long as I can because I know tomorrow, I'm going to have lead feet or half a lung. Why, why, why?  Why can't I recreate that high every day?  Funny thing is that I know I can't and yet I just keep trying, I guess because eventually, after many, many tries, I'll have one of those great runs again.  And it will be worth every crappy run in between just to have that feeling again, the feeling of being able to run to end of the world and back.