The wind in the hair, the breeze on the face, the sweat on the brow, the pain in the knees, back, neck and tush.

All of these are associated with bike riding. But you might be able to eliminate some of the pain by making sure your bike fits your body properly. Bikes can be adjusted to achieve a better fit for you and make them more comfortable to ride.

"A lot of people ride a bike and have aches and pains, and they accept those aches and pains as part of riding a bike," says bike-fitter, competitive cyclist and triathlete Nancy McElwain. But "riding a bike does not have to be painful."

The American Physical Therapy Association is trying to call attention to the importance of bike fit as a means of injury prevention by tackling problems and solutions on its Web site and by providing a downloadable brochure.

"If you have a poorly fit bike, it will predispose you to injury and what I call bicycle-related pain syndromes, and those are simply, 'It hurts when I bike,'" says Erik Moen, a member of the association who's also a competitive cyclist and coach in Seattle. "It might hurt in your shoulder or neck, (cause) saddle discomfort, foot discomfort, hand discomfort."

Also, "the fit of the bicycle affects how well the bicycle handles," says Moen, a physical therapist and certified strength and conditioning specialist. "There are certain fit parameters that will make the bike handle the way it should or make it handle very sloppily, if you will, or it'll also limit your ability to effectively corner or come to a stop."

Furthermore, "if your bike is poorly fit, your ability to pedal the bike well and with good economy is limited," he says.

"I would say that all of us who ride a lot pay really close attention to that," says Dr. John Mandrola, a member of a racing team in Louisville, Ky., and a physician with Cardiovascular Associates.

But bike fit also is relevant to more casual cyclists, he says, because "one of the biggest complaints that I hear about using a bike as fitness is that the position is uncomfortable or it's hard to stay in that position long enough to exercise," Mandrola says.

Helpful advice can be gleaned from groups like local racing clubs, physical therapists, bike shop staff and individuals-- such as McElwain -- who specialize in bike fit.

"When I go about fitting a person on a bike, I start down at the pedals and then move up to the saddle; and then we move up to the handlebars from there," Moen says. "The position of those elements affects the other parts in between."

The biggest mistake people make is "usually their seats aren't high enough," says Louisville bike shop owner Chuck Davis.

Poor saddle positioning -- either too high or too low -- can lead to low-back pain, says Bill Eisner, a Louisville physical therapist who's also a competitive cyclist. Others warn seats that are too low can lead to knee problems, and tendinitis can be the result of a saddle that's too high.

Eisner says it's important for the saddle to be level. If it's tipped too far forward, there could be too much pressure on the arms and shoulders and the hands could go numb, he said. "If it's tilted too far back, as in the nose of the saddle is tipped upward, that can give you pain from the saddle itself -- groin pain, different things like that."

McElwain says women have had difficulty with bike fit over the years because "historically, bikes were proportioned with men in mind," but now there are some women-specific bikes more suitable to a woman's body.

Handlebars should be within "a comfortable reach," so that "you don't have to excessively elevate your shoulders to get up to the handlebars or reach too far down to get to the handlebars," Moen says. "If the fit of your bicycle makes your arms lock out to support your weight, generally something is off, whether it's a handlebar position or a saddle position issue. If your hands are going numb, that's a bad sign."

Handlebar position can contribute to neck and shoulder pain, Eisner says.

Different cyclists have different needs. For instance, "on a racing bike, you're bent over quite a bit... but most recreational cyclists want to sit more upright," Davis says "The more you're bent over, the more power and drive you get as far as going fast, but if you're just riding in the neighborhood with the kids, it hurts your back to be bent over like that."

Trunk position and shoulder angle: For the recreational rider, trunk position should be 40-80 degrees from horizontal. Shoulder angle should be 80-90 degrees. For the road cyclist, trunk position should be 30-40 degrees and shoulder angle should be 90-100 degrees.

The handlebars: Handlebar position will affect your hand, shoulder, neck, and back comfort as well as the handling of your bicycle. For the road cyclist, correct handlebar positioning will provide better pedalling efficiency, aerodynamics, and improved safety with cornering and braking. The width of the recreational rider's handlebars should allow hands to be slightly wider than shoulders. For the road cyclist, hands should be approximately 2 centimetres wider than the shoulders for comfort and to help ensure good handling of the bicycle.

Knee to pedal: A physical therapist can measure the angle of your knee to the pedal. The closer the angle is to 35 degrees, the better function you will have with less stress on the knee. For the recreational cyclist, the angle should be 35-45 degrees. The road cyclist should have a 30-35 degree angle.

The saddle: The saddle on your bike should be level. If the saddle tips downward, pressure will be placed on your hands and lower back. The saddle also should be a comfortable distance from the handlebars -- too close, and extra weight will be placed on your mid-back and arms; too far away, and you may put extra strain on your lower back and neck.

Foot to pedal: Position the ball of your foot over the pedal spindle for the best leverage, comfort and efficiency. A stiff-soled shoe is best for comfort and performance.

Source: American Physical Therapy Association. On the Web: www.apta.org