DID YOU KNOW?
While bicycling, a rider’s legs go up and down as many as 5,000 times per hour.

To paraphrase a popular children's song: The wheels on the bike go round and round, round and round. The legs on the bike go up and down, up and down. The knees on the bike go ouch, ouch, ouch! Ouch, ouch, ouch! If your knees sing this song, then consider this: Knee pain is one of the most common cycling ailments—and it's almost always preventable.

Sources of knee pain
A handful of culprits account for the majority of cycling knee pain and injury: bad bike fit, improper training, and poor technique. All three create increased stress on the knee joint, an effect magnified by cycling's repetitive motions. Cycling pain most commonly occurs on the front of the knee, usually underneath the kneecap or just above it near the top of the knee joint. To prevent it, you should ride in a position that generates minimum knee stress, train so that overuse injuries are avoided, and pedal with appropriate gears and cadences.

A fitting solution
Bike fit is critical, especially seat position. "Most people tend to ride with the saddle too low and too far back," notes Dr. Chad Asplund, director of sports medicine at Eisenhower Army Medical Center in Fort Gordon, Ga., who has written extensively about cycling injuries and prevention. "It's easier to use the quads for more power when the saddle is farther back, but it also causes more pressure on the knees."

To adjust the saddle properly, have a friend hold your bike in place, then position your feet so that the pedals and crank shafts are in a straight line parallel to the ground. The front of your forward knee should be directly over the ball of your foot and the axle of the pedal; if not, move the saddle forward or backward accordingly.

Next, check saddle height. If the seat is too high, your hips will rock back and forth as you pedal; lower the saddle to the point where this hip motion ceases. Double-check the adjustment by evaluating how much your knees flex at the lowest point in the pedaling motion; an angle of 25-30 degrees is considered optimal.

Clip-in cycling shoes can also contribute to knee pain. Everybody has a natural foot alignment that creates the least stress on the lower legs and knees. If unattached, the foot freely rotates to the proper position. But clip-ins may lock the foot into a suboptimal position that can lead to knee pain and injury. Bike cleats feature an element of "float," a few degrees of movement in either direction, helping the foot to achieve its optimal position. Compare your natural, unclipped foot position to its locked-in state to ensure they are the same.

Common training mistakes
In the Northeast, many cyclists go through a period of winter dormancy. When spring arrives, there is a temptation to ride harder and longer than winter-wasted muscles can handle. Overly fatigued muscles tend to tighten, become less flexible, and increase the amount of pressure on the knee. To avoid this, Asplund recommends the following: "Start out at 50-60 percent of your longest ride from the fall season and then increase by 10 percent a week."

Weak technique
Cyclists, especially casual riders, tend to make two common mistakes. First, they tend to push higher gears than they should, especially on uphill section. (Higher gears require greater effort, increasing knee stress.) Second, they tend to ride at low cadences (the number of times the pedals make a full rotation per minute). Both increase the power required to turn the pedals—and thus amplify the force (and stress) applied to the knee. "Most people who are new to cycling tend to pedal at a cadence in the 70-80 rpm range, so they have to generate more power than is optimal," Asplund explains. "A more correct way to pedal would be somewhere around 90 rpm." These two factors are related; pushing lower gears also makes it easier to pedal at a higher cadence. A variety of easy-to-install cadence sensors are available, starting around $50.

Warning signs
Cycling should be a pain-free activity. It's one thing to feel pleasantly fatigued and sore after a ride. It's another thing entirely if you experience knee pain while you pedal. "Anytime you have pain during an activity should make you think," Asplund says. "Sharp pain in a specific location is always a concern and any knee pain that causes swelling should definitely be looked into. The worst thing people can do early in the season is ignore small pains."