Imagine you've been sitting on the couch every afternoon for years. So you're sitting on the couch.

BRAIN
Let's go ride 5 miles.

BODY
Ride what?

You get on your bike and ride 5 miles.

BRAIN
How was that?

BODY
Really bad. There was rubbing and muscles are tired and we can't breathe and we hated it.


Two days later:
BRAIN
Let's go ride 5 miles.

BODY
Aw crap! That was so uncomfortable last time! Okay, I'll do it, but next time...just you wait.

You get on your bike again and ride 5 miles.

BRAIN
How was that?

BODY
Not as bad as I expected. But I'm still going to change some things, you won't fool me again.

Three days later:
BRAIN
Let's go ride.

BODY
Oh yeah, I'm ready this time. Lungs are cleared out, heart knows what's coming, muscles know where the nutrients are. Let's do it. 5 miles!

BRAIN
Nope, let's go 10 today.

BODY
Wait, what?


This goes on for a few weeks. Your brain is sneaky and cruel to your body, so it keeps bumping up the mileage every other ride. You work up to 25 or 30 miles in a single ride. Your body doesn't have much choice, so it adds armor wherever it's needed to survive these "long" rides.

This is the novice phase.

Your lungs and heart and muscles improve rapidly. It's not conditioning. It's learning. It's routing oxygen and nutrients, establishing motor patterns, and creating a "bike ride" preset for your body. You aren't stronger. Your body is just "smarter." You're almost ready to train...

And that's where the beginner phase, well, begins.