My first official class was yesterday. I was a nervous wreck. Would it be mostly guys? Would they all be 6′3″ professional boxers? Would I hold them back?

Walking into class, I was surprised by the numbers. There’s maybe a dozen people in my class, half of them women. I’m instantly more at ease.

We start with some simple warm-ups and then a solid stretch.

The instructor demonstrates a roundhouse kick and directs us to a line of punching bags in the center of the room.

I give it a go, shooting out my leg for my first kick.

Now, I’m a thin girl, blessed with a high metabolism rate, but I’m far from toned. My body fully refuses to cooperate with my already inflated self-image as a bad ass, crime-fighting dominator. The black punching back bag barely moves.

I watch my partner—a shorter, thinner girl—throw her own roundhouse kicks. The bag obligingly scoots across the floor. Holy crap! If she can do it, surely I can too.

Rotate, Hips! Extend, Leg! Put some power behind it.

My mind is totally into it, but my body is completely unprepared to put power behind anything. Reset my stance. Try again. Ugh. My ankle starts to twinge a little. This… is hard.