Good bike fit can make difference between fun and pain

Wednesday, October 25, 2006

The millions of weekend bicycle enthusiasts and competitive riders in the United States may be at risk for injury if they're riding a bicycle that's not fitted to them correctly, according to the American Physical Therapy Association.


	Matt Freed, Post-Gazette The bike bridge in Ohiopyle is popular with bicyclists. A good fit between rider and bike makes the trip go smoothly. Click photo for larger image.

APTA member Erik Moen, PT, CSCS, a Seattle-based "Elite Level" coach through the United States Cycling Federation, says, "The first thing I ask any patient complaining of bicycling-related pain is to bring the bicycle in to check for a proper fit. In most instances, a poor bike fit is at the root of their problem."

Mr. Moen, who races on the road and in indoor velodromes, says that the most common bike fit errors include saddle heights that are either too high or too low, handlebar reach that is either too long or too short, and misalignments of the pedal and shoe. For proper bike fit, he recommends:

Saddle

Be sure that the saddle is level. If you are sliding too far forward from a forward-tilting saddle, too much weight is being placed on your hands, arms, and lower back. If the seat is tilted backward, you may place undue strain on your lower back and possibly experience saddle-related pain. A physical therapist can measure proper saddle height by measuring knee angle at the most extended position of the knee in common pedaling.

The saddle also should be a comfortable distance from the handlebars. If it is too close, extra weight will be placed on the mid-back and arms; too far away and extra strain may be placed on the lower back and neck.

Handlebars

Handlebar position will affect hand, shoulder, neck, and back comfort. The higher the handlebars, the more weight will be placed on the saddle. Generally, taller riders should have lower handlebars in relation to the height of the saddle. According to Mr. Moen, "Proper handlebar position allows for shoulders to roughly make a 90 degree angle between the humerus and trunk." Trunk angle for the road bike cyclist is 25-35 degrees and for comfort/recreational riding is 35-90 degrees.

Knee to pedal

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

Foot to pedal

The ball of the foot should be positioned over the pedal spindle for the best leverage, comfort, and efficiency. A stiff-soled shoe is best for comfort and performance.

"Pedaling is a skilled activity that requires aerobic conditioning," Mr. Moen says. "You should make it your goal to work toward pedaling at 80-90 revolutions per minute (advanced at 90-105 rpm). Pedaling at this rate will lessen your chance of injury."

Physical condition

"Good flexibility of the hamstrings, quadriceps, and gluteal muscles is crucial because these muscles generate the majority of the pedaling force and must ideally move through the pedal-stroke in 80-90 revolutions per minute." Mr. Moen adds, "Proper stretching, balance, and flexibility exercises help with coordination of cycling-related skills such as breaking and cornering." Mr. Moen also cautions that changes in riders' strength and flexibility affect the ability to attain certain positions on the bicycle and also may require them to re-examine their bike fit.

Mr. Moen points to bicycle accessories on the market -- such as softer handlebar tape, shock absorbers for the seat post and front fork, cut-out saddles, and wider tires -- that help to bring comfort to the sport. "Cycling should be about enjoyment, not pain," concludes Mr. Moen.

Posture tips

Some additional tips from the APTA to avoid injuries related to bike fit:

Change hand position on the handlebars frequently for upper body comfort.