Are You Living It?

Bike fitting is more than just plugging in body part measurements and asking a computer to tell you the correct dimensions of the seat, pedal, handlebar geometry. This type of fitting sounds very scientific, because it uses a computer, but those measurements don’t tell you how your body mechanics will relate to the bike. And remember, your comfort and efficiency on the bike are all about ease of movement or lack thereof. This type of formula-based set up, while appropriate as an initial match of the bike for a given rider, should not be considered a true bike fit. I have clients complain that they have discomfort while on the bike, even after they have had the bike fit to them at the bike shop. This is usually because the bike has been set up for their measurements, but not truly fitted to them.

Many offered bike fits are based solely on measurements and a riders physical limitations or correctable bio-mechanical errors are not fully addressed.  Usually this is due to the bike shop mechanic’s limited knowledge of bio-mechanics. Remember, they are bike mechanic’s, they are trained to fix bikes not riders. Not that some bike mechanics are not also excellent bike fitters, but these are a separate set of skills. The bike mechanic may be readily able to notice that a person is so stiff that they can not bend forward to the drops, but the mechanic may not see where the flexibility is limited. In this instance the rider could have limited motion in the hamstrings, gluteal muscles, low back, lats, restricted motion of the sciatic nerve, or just that their bibs are way too small.  Any one of these, or combination of these, may limit the riders ability to flex forward correctly. Other causes of pain while riding can be caused by muscles being overused due to subtle errors in body position. The rider may look and feel comfortable while pedaling, but certain muscles are being used that should be relaxed. These types of positioning errors usually show up as pain or discomfort after being on the bike for extended periods of time. It can be difficult to determine their origin without bio-mechanical knowledge and focused examination of the rider, while on the bike.

The number one question that needs to be answered before fitting the bike to the rider is, “what is the goal of this specific fit?”. Are you striving for comfort, efficiency, power output, aerodynamics, or any combination of these. With that answered the fit progression may look something like this:

If the bike has never been ridden by the rider, the initial bike set up is based on commonly used relationship of the riders body measurements and joint angles while seated on the bike. The cyclist rides on a trainer or bicycle treadmill during the fitting process. This is usually preferred to a free ride as the fitter can move around the bike and view all aspects easily. As the rider warms up, riding easily, the fitter looks for any obvious fit problems.Checking the position of the ankles at the bottom of the pedal stroke, excessive motion of the body, the rider is also asked if they have any current discomfort while on the bike. At this point baseline power output and/or heart rate may also be noted. Any position or motion abnormalities are noted (video is very useful for this, as you can see the effects of each change). Then the fit begins in earnest. The bike is incrementally changed toward the goal of the fit. Seat height and forward/rearward seat position is focused on first, until the rider is nearest the fit goal. Next the handlebars are moved as needed to optimize the fit goal. During all of these changes, the bio-mechanics of the rider are monitored to avoid negative effects on comfort or decreased performance. A change in only a few millimeters, in some instances, can switch a specific muscle on or off and lead to a significant change in efficiency, comfort and power output. Heart rate and power measurements can also be used to monitor efficiency and energy expenditure.

The best results are obtained by getting your flexibility and motion corrected, before or in conjunction with your bike fit, and can make even greater improvements in your on bike comfort, efficiency and power output.

For many riders it is surprising how much better their bike feels after a good bike fit. Others may find the reason they have never been very comfortable, or may have been riding a bike that was just the wrong size for thier body. In any case, a good bike fit will benefit most riders and they will soon be enjoying their cycling passion even more.