By Patricia Staszak, PT
Basic Principles of Bike Fit
Fitting a bike properly to a person is a very detailed task and one that is best served by a visit to someone who specializes in this area – either a reputable bike shop in the area or to a physical therapist or fitness professional. Although I will not be able to cover all the nuances of proper bike fit, I would like to review a few basis principles of the fit simple measurements that you can use to examine your position on your bike.
There are two different sections to the bike: the power plant and the cockpit. The power plant is the seat, seat post, and pedals, and is important to generate power to the rear wheel. The cockpit is the handlebars and stem and it establishes the posture of your torso and provides comfort, stabilization, and control. The power plant is the first area that is adjusted on a bike fit, and I will review simple steps to check your position. Unfortunately, adjusting the cockpit is too intricate to explain in this article.
To find the correct position of your power plant, perform the following steps. First, when placing your foot on the pedal, line up the ball of your foot with the axle. This will help you generate power. To set the seat height, put your pedal at its lowest point; there should be a slight bend in your knee. To set the position of the seat fore or aft, drop a plumb line from the most forward part of the kneecap; it should line up with the ball of the foot and axle of the pedal with the pedal at the 3 o’clock position and foot parallel to floor. If the plumb line is forward to the axle, move the seat back, and if it is behind, it move the seat back and if it is behind it move the seat forward.
Oftentimes, when clients feel too much pressure through their arms, their first instinct is to move their seat forward, but this actually can shift their body weight forward and make the problem worse. If more of the body weight is absorbed through the seat there is actually less stress through the arms. A cockpit that is too close, too far, or too low, can cause increased stress through your hands and shoulders. If you are having pain or do not feel comfortable on the bike make sure the power plant position is correct, and if you still have problems, it is probably a cockpit problem and may require some further investigation.