Ethan, our 24 year-old son who recently enlisted in the army, is continuing to surprise me with the changes he is making. Perhaps none of these changes is more shocking than his sudden and determined effort to get in shape. With the exception of PE classes in school and a short-lived career on the high school tennis team, the only part of his body that got regular exercise was his thumbs from playing video games.

However, now he calls me up update me on how many push-ups he can do and to discuss his training regimen. He was obviously very proud when he told me that while he is waiting for the microwave to beep, he’ll drop and knock off 10 or 20 push-ups. Who is this child and what have you done with my inert son?

The motivation behind his newfound interest in exercise is the humiliation he imagines he will feel if he doesn’t pass the physical fitness test at the start of basic training. Incoming soldiers must have a certain level of physical fitness which includes doing pushups, sit ups and a two-mile run in 13 minutes or else they will get put into the so-called “fat class.” For a skinny kid like Ethan, the fear having to do remedial PT (physical training) is already kicking his butt.

He has also told us how he is really looking forward to getting buff in basic training. He has realized that he could look really awesome with defined abs and guns (of the bicep variety) but he hasn’t had the motivation to do it on his own. I guess a drill sergeant is the ultimate personal trainer.

Until recently, we thought his younger sister had gotten all the physical exercise genes in the family. It didn’t matter that she was born without a left hand; she has always sought out challenging physical activities. Whether it was doing rhythmic gymnastics, martial arts, or acrobatics, she has always had the need to sweat. She’s like me in that sense.

She thought it was pretty amusing when we told her that after Ethan completes basic training, she would no longer be able to take him down in a fight. Actually, she’s very proud that he is finally seeing what his physical potential is. I know her respect for him has grown.

Ethan’s biggest concern right now is a sore knee that is preventing him from keeping up his training schedule for running. Soreness is a new experience for him. Even when you’re in your twenties, if you go from zero to 60 in a short amount of time, you’re bound to pay the price.

So as someone who used to run a lot and still loves going to the gym everyday, I told him to take a couple of ibuprofen and let it rest for a day or two. A little bit of discomfort? He should get used to it. Basic training will be nine weeks of intense discomfort.