The problem with lifting too little

From MSNBC:

You've likely heard that with exercise, it all adds up. Every minute you spend climbing stairs, swimming laps or raking leaves counts toward the half hour a day of physical activity that's recommended for keeping your heart healthy. Just as long as you get moving, you're on the right track.

But when it comes to keeping your muscles strong, it's not that simple.

"Cardiovascular and strength training really are different," says Stephen C. Glass, professor of exercise physiology and coordinator of the human performance lab at Grand Valley State University in Allendale, Mich. "You can't just lift a pencil a thousand times," he says, and think that will boost your biceps.

That's an exaggerated example, of course, but plenty of gym-goers are working out with weights that are doing little more for them than a pencil, according to Glass and other fitness experts.

"If you just sit in a weight room and observe most people, I would say 80 percent are lifting inappropriately," Glass says.

Most gyms have their share of power-lifters who make the mistake of quickly jerking very heavy weights, a practice that can cause injuries. But a more common problem, he notes, is the failure to lift enough weight to build strength.

In a recent study published in the Journal of Strength and Conditioning Research, Glass found that everyone in a small group of novice weightlifters failed to use enough resistance to do them much good.

The study was meant to mimic what typically happens when beginners go to a gym and embark on a weight program with minimal supervision. Thirteen male and 17 female college students were observed using several weight machines, such as the seated bench press and the biceps curl. And all of the study participants consistently chose weight loads that were well below the minimum recommended level for building strength — 60 percent of their one repetition maximum (1RM).

Instead, they were lifting at intensities of 42 percent to 57 percent of their 1RM.

"They were picking really light weights," Glass says.

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