Pushups and Crunches

Do some pushups and crunches. If you’re bored, you might as well start getting in shape. You can do pushups and crunches right there on the floor next to your desk (or go outside if you’re worried about your coworkers seeing you). Or walk up some steps, or do squats and lunges without weights, or dips in your chair, or butt squeezes (that means squeeze your own butt, not your coworkers’).

Push-Ups

Push-ups win the triple crown: they work the chest, shoulders and arm muscles -- and as a bonus, even to some extent the abdominal muscles. Push-ups build the shoulders, broaden and flatten the pectoral muscles and accent the triceps -- the muscle at the back of the upper arm -- to add a nice bit of self-assurance to your profile.

Like crunches, they're highly adaptable and you can vary your workout to include many push-up variations. For example, performing the push-up on a decline activates the shoulders more, while narrowing the width wakes up the triceps.

Crunches

There's no downside to crunches, which have all but replaced sit-ups as the most popular abdominal exercise. The basic crunch works the rectus abdominus, which is the long flat sheath of muscle that girds the front of the abdomen. That's the muscle that gives rise to the holy six-pack of abs, at least to the very lean and very diligent.

The basic crunch works the upper end of the rectus abdominus more than the lower end. But one of the great things about the crunch is that it's supremely tweakable. So with your feet off the floor for a supine bicycle crunch, for example, you'll be giving those obliques the business. And, you will enhance the power of the crunch by performing them on a stability ball; this exercise ranks No. 3 in the American Council on Exercises list of best abdominal exercises.