There is a great scene in The Other Guys, where Mark Wahlberg pumps his arms up and down and shouts, “I want to be a peacock.” His chicken-like pose works for the movie, but would be totally wrong in the real world. Peacocks don’t pump their arms and jump up and down. They are more haughty divas on the catwalk than irate cop.

Have you ever wondered about good posture in animals? About how a giraffe maintains its poise in spite of an ungainly long neck? About how a porcupine, which looks horrendously ill-proportioned (big body, tiny legs), still manages to run elegantly? Harvard University professor Andrew Biewener runs a lab that studies animal locomotion. And one of his early discoveries was about why large animals with relatively small bones and muscles move so elegantly, without overloading their skeletons. The reason: good posture.

When I’m stuck in traffic, I tend to slump back into the seat and curse fluently. One day, I tried something different. Since my back hurt, I decided to sit upright, moving a couple of inches forward instead of leaning back, as I usually did. The pain didn’t go away, but there was a side benefit. I discovered I had to engage my core muscles to sit upright as the driver zigzagged his way through traffic. I have been doing this ever since.

Engaging your core while in the car, bus or autorickshaw is simple. All you need to do is make sure that your back doesn’t lean against the backrest. Sit a few inches forward in the seat. No matter how much the vehicle jerks or turns, don’t lean back. If possible, pretend that there is a rod going through your spine. Or pretend you are a peacock.

Stay alert, of course, to ensure the jerks or sudden brakes don’t injure you. But hold the forward position for the length of the ride. You will be surprised at how tight your abs feel at the end of the trip.

This exercise works better when you are stuck in stop-and-go traffic and have a driver who’s trying to beat the odds. You are trying to hold your position by tightening your core during the jerky starts and stops. After a 45-minute car ride, with you sitting in this position, you will be ready for the advanced level.

This too is simple practice. You lift your feet off the floor while sitting in the car. Just lift up your feet, oh, maybe a couple of inches. That’s it. Hold your position. After a while, your thighs will start to hurt—that is the objective.

Harder than you think, isn’t it? Your back has no support, so you have to rely on your core to sit upright. Stay for 15 minutes in this position, if you can.

Sitting upright has another benefit: It improves your willpower. Studies have shown that students who don’t slouch build up discipline and willpower over time. No matter where you are, reminding yourself to sit upright and have good posture has far-reaching benefits that have nothing to do with your body muscles.

The great thing is that you can do this workout during a commute. Every long commute, then, becomes a gift. Isn’t that great?

Shoba Narayan is an expert sitter-without-slouching on car rides. The fact that she slouches everywhere else is besides the point. Write to her with your tips, tricks and short cuts. She blogs at Shobanarayan.com, tweets at @shobanarayan and Instagrams at #shobanarayan.