Intro: Since their invention in the late 1700s, bicycles have been enjoyed by people from 2 to 92. You'll enjoy the ride more, however, if you aren't huffing and puffing. In just two weeks, you can build up your endurance for cycling by following a modest program of aerobic exercises and stretching. The best advice for avoiding injury? Wear a helmet. They're not just for children.
Approximate calories burned per hour: 375-600, depending on speed.
Popularity: 54 million Americans are recreational cyclists. About 6.6 million women and 9 million men cycle more than 52 days a year.
Safety equipment: Helmet, sensible shoes, a bell or horn, and a bicycle with seat and handlebars set at the correct height. If you ride at dusk, use a bike light and reflectors and wear reflective clothing. Long-distance cyclists need gloves, padded shorts and eye goggles. Ride the same direction as traffic and don't wear headphones.
Common injuries: Pedaling a bicycle is easy on the body as long as the bike fits properly.
A seat set too low can cause knee pain; a seat set too high can cause hamstring pain. Your handlebars should be adjusted so that 70 percent of your weight is on the saddle and 30 percent on the handlebars. Most injuries from bike riding come from falling off -- scrapes, cuts, fractures of collarbone, shoulder, wrist or arm, or head injuries.
Ride on the wrong saddle, and you can get groin pain and chafing and blistering on your, uh, seat. Riding a bike in flexible sneakers can cause arch pain, so wear fairly stiff shoes. As your mother used to say, never ride a bike in flip-flops!
Aerobic training: To complement the aerobic activity of cycling, try swimming, stair machine workouts, treadmills or in-line skating.
Be sure to warm up and cool down by cycling slowly at the beginning and end of rides. To increase endurance, use the middle third of your ride to do five or six 20-second bursts of speed. You also can increase your fitness by doing power interval training on a stationary bike, although it does not precisely mimic the real thing.
Weight training: Boost your strength and power with a weight-training program 2-3 times a week. Use a general circuit training program or free weights.
Stretches: After riding slowly for a few minutes, use a forced stop at a stoplight to take a stretching break. Focus on quadriceps, calves, hamstrings and the gluteal area. Proper stretching can help avoid back and heel pain. Three sample stretches are on this page.
Tip: If you fall off a bike, avoid injuries by tossing the bike away from you so it doesn't hit you. Then "think like a ball" -- tuck and roll as you hit the ground, advises Dr. Andrew Feldman, author of "The Jock Doc's Body Repair Kit" (St. Martin Griffin, $16.95).
Bicycling injuries are the most common recreational injury for people ages 35 to 54 and accounted for more than 65,000 trips to emergency rooms in 1998.
