OUTSIDE: Why release another ­version of the same product?
HORTON: P90X is a combination of a lot of things, but it’s mainly conditioning. P90X2 ($120; beachbody.com) is performance-based training for athletes. It’s indoor training for the outside world.

How will the program make outdoor athletes better at their sports?
We get into more functional, balanced-core, and stability work. In P90X, you’re sitting and doing biceps curls. In P90X2, we’ve got you in a Warrior III yoga pose doing biceps curls. We’ve got you doing push-ups on four medicine balls.

The programs are structured on the idea of muscle confusion. Isn’t that just a smart marketing term?
Muscle confusion and periodization training—they’re just variety in fitness. For P90X, I spent a year talking to experts and came away thinking that people struggle because they’re doing these quasi-myopic exercise routines. Weights are great, but they’re just weights. Pilates is phenomenal, but it’s just Pilates. Same with yoga. They’re all great, but you’re missing out on other aspects of fitness if you do just one.
 
And variety in training will lead to ­better performance?
If you’re skiing down a couloir and the pitch is 40 degrees, and you get kicked off because you hit some slough, you need balance and power to pull it back in and save your ass. That’s why the yoga is in there, along with strength moves.

You preach a lot about attacking your weaknesses. What’s yours?
I’m a 53-year-old skier, so I’m always working on strength, flexibility, and balance, because typically all of those things go south in guys my age. I’m jumping off 15-foot cliffs and not landing on my back or stomping on my feet. If it wasn’t for my fitness techniques, I couldn’t do that.