Are you a jiggler? Do you tap your fingers or feet, bounce your heels up and down, or knock your knees together while sitting? That can be good — or if you're a competitive athlete, bad.

First the good. There have been many scientific and medical studies examining different aspects of jiggling. One overall conclusion: Lean people jiggle. Obese people do not.

There are a variety of expert opinions about this fact, but not many causative links. In other words, lean people who stop jiggling don't become obese, and obese people who begin methodically jiggling don't get lean. But there's still a close relationship between calories burned and calories stored as fat when it comes to jiggling or fidgeting.

Suppose you're an active, athletic person who spends most of your waking hours sitting; sitting while being transported to and from work, sitting while at work, then sitting in the evening for dinner and a bit of TV. If you're a five-day-a-week person, the only time you really have for intense exercise is on the weekend.

Maybe you're a serious enough athlete so that you push yourself to train before or after work. But part of the long-term benefits of an hour or so of intense activity is lost when it's preceded by, or followed by, hours of sedentary sitting. A compulsion toward fidgeting may be the body's way of calling for a little action, a bit more movement if muscles haven't been used during the passing minutes.

Skip workout for jiggling?

Jiggling will never replace diet and exercise when it comes to building muscle and losing weight, but any kind of movement, no matter how small, still burns calories. It's been estimated by a number of scientists that despite a sedentary job, daily movements such as frequent wiggling in your chair, foot or finger tapping and other forms of fidgeting, will burn at least 200 calories a day.

Add to this by getting out of your chair often. Even if you just take a few steps, or take a short walk to the break room or up and down a stairway once an hour, it will activate your muscles and do a lot to keep them from adjusting — or atrophying — to your day of sitting. You'll keep a lot more of the "training effect" that makes you a good athlete.

Now for the bad part: overtraining. If you're a competitive athlete with a contest or competition coming up, you'll want to be very careful about how much, and how actively, you jiggle.

The athletic fidgeter

As an example, take "Bobby." He's a skier who enjoys racing, and enters every available race at his two local resorts. Most of his skiing is done at night, after work. It's his main form of exercise; he doesn't belong to a gym.

But Bobby began to notice that after a night of training, his legs felt overworked and slightly sore the next day. It took time, but he finally realized the connection between doing three or four hours of hard skiing and his habit of vigorously jiggling his legs whenever he was seated. The constant tension of the seated movement overtrained his quadriceps and hamstrings, so those muscles were always exhausted on race night.

It was hard to do, but Bobby began to control his fidgeting the day before and the day after a training night. His results improved immediately, and are still improving.

Of course, if he were in better condition, his muscles would not be depleted of their energy by simple jiggling. The fact remains that a little movement while sitting at a desk will help burn a few calories and activate a few muscle fibers. but if you're an athlete, do a real workout rather than just a jiggle.