High-tech gadgets and shiny exercise equipment are “musts” for any big city gym. So it’s easy to lose sight of the many benefits of old-fashioned, low-tech, equipment-free bodyweight exercises. I’m talking specifically about the plain old push-up.

Push-ups are a terrific way to build upper-body strength and endurance. They’re also a symbol of fitness and vigor. (Ask anyone who watched 71-year-old Jack Palance drop to the floor and do his now-famous one-handed push-up routine during his Oscar acceptance speech.) Push-ups engage multiple muscle groups, including the chest, the triceps, and the shoulders. Plus, they require abdominal strength for stability. And you can do them anywhere.

Push-ups are particularly valuable for older people. As science reporter Tara Parker Pope says, “The ability to do them more than once and with proper form is an impo rtant indicator of the capacity to withstand the rigors of aging.”

Here’s how to do a push-up using proper form:

Keeping your back straight, put your palms flat on the floor a little wider than your chest.

Bend your elbows to lower your shoulders and upper body till your nose is almost touching the floor. Then straighten your elbows to raise back up. Be sure to keep your neck in line with your body. (A good illustration of how to do push-ups can be found at ABC-of-Fitness.com.) Women – who have about one-fifth less muscle than men to begin with – can start with their knees bent and build up to the harder version.

If you really want to test yourself, the Army’s standards are the way to go. Passing the test for the military requires at least 24 repetitions for a 37- to 41-year-old man, and six for a woman in the same age group. Want to be better than average? Go for 34 if you’re a guy and 13 (or more) if you’re a woman.

[Ed. Note: Dr. Jonny Bowden is a nationally known expert on weight loss, nutrition, and health. He’s the author of the new book The Most Effective Natural Cures on Earth. .]