I used to be the guy who could pull 405 at 225. CrossFit most mornings, never competed, didn't need to. I knew what my body could do.

Then a car put me in a coma for ten days.

When I woke up I had to learn how my own head worked again. I did it the only way I knew, by training. Triathlons. Mud races. I got into law school. I left before I finished, came home, and had a son.

I've always been risk tolerant, so sales was a natural fit. Ten years of it, most of them at a desk, paid on what I closed. The gym became something I did when the week let me, which is to say not much. I told myself I was still in shape. Calipers said 15 percent. I believed them.

About four years ago my back decided it was done carrying me. Days in bed. Days where putting on socks was the hard part of the morning. I hung upside down on an inversion table. I saw a chiropractor three times a week. I paid people to make it stop hurting and nobody made me stronger.

This September I got a DEXA scan because I was curious. It said 24.8 percent.

That's the number that ended the guessing. I've always built things, I modded Xbox consoles as a kid and I build my own computers, so I built this the same way: a watch that files every set I lift and every night I sleep, a scale and a tape every Sunday, and one decision a week made by the numbers, not by how I feel on a Tuesday.

Every one of those numbers goes on this page. The good weeks and the ones where the scale goes the wrong way. The back days. The lifts coming back.

I'm not doing this because I found a secret. I'm doing it because I'm a dad with a desk job and a bad back who finally measured what was really going on, and I'd bet you haven't either.

In January I'm taking ten men through the same thing.