Six Years In - What I've Learned as a Bike Fitter: Lesson #4 - Be Wary of Fitting to Poor Function and Why I Don't Like Flipping Stems Up

I’ve read in other fitting blogs or perhaps overheard in a fitting seminar or two about the relationship between fitting the client to the bike or fitting the bike to the client.  There’s a great article about that here.

The premise of this dyadic relationship is that far too often the default method of fitting a client to a bike involves a machine with limited and predetermined geometry, which limits the range of adjustments a fitter can make.  It could very well be the wrong size and just the wrong bike  It’s always a compromise if the bike just doesn’t work for a particular client.  Sometimes, however, that’s what we’re stuck with and a fitter just has to make due.  

This leads to the second alternative:  fit the bike to the client.  For obvious reasons this is infinitely better, and forms the basis of my Bike Finder Fit  I first fit a subject on my Purely Custom adjustable fit bike, in the process establishing the ideal saddle choice and crank length, and the in the course of the fit process I establish fit coordinates. I can then use simple calculations to convert these coordinates into frame geometry coordinates.  We can then filter through and find the best combination of frame geometry and stem and spacer choice to match what we consider this ideal fit.  

It’s a great approach, and I find them fun and innately satisfying because they come close to providing a sense of mathematical certainty to optimal bike fit, which is in contrast to the mildly demoralizing feeling of doing something somewhat unorthodox to a bike configuration to make an unsuitable bike acceptable. A client starts off the right bike and the right fit, which maximizes the possibility of continued enjoyment on the bike and of the sport.

Nevertheless, the bike fit first approach is not without its own set of pitfalls, and as much as I or anyone else is attracted to a system that provides absolute certainty, the universe, as we know, is more complex.

Particularly with case of new riders, they often lack the proprioceptive sense of truly understanding what feels right and if they feel more fluid on the bike - they can’t quite recognize that dialed in feeling.  

In addition, new riders aren’t necessarily adapted to riding a bike and spending hours hunched over a contraption that wasn’t really conceived by humankind to provide the best biomechanical position for the human body.  We all have to adapt to the bicycle because it’s an inherently unnatural act.  But as humans, we also have a remarkable ability to adapt to any number of different physical demands and circumstances, and the human powered bicycle is amazing in its ability to convert human mechanical energy into forward speed.

Through repetition and training, not only to new riders become better at riding their bikes; not only does a rider get more fit, but his ability to maintain proper posture in this innately unnatural act improves.  Core activation and strength improves, flexibility increases, the rider becomes more adept and comfortable maintaining proper form.  Riders naturally adapt.  This has two implications:

Your position will change over time.  What might be optimal one day, through days, weeks and months of riding, or through progressive or induced changes in function, will be now be sub-optimal.  Riders improve, not only with respect to fitness and strength, but through improvements in on-the-bike posture.

Anticipating these changes brings us to the second implication:  I try not to fully fit to dysfunction.  If a rider prefers a position based on perceived comfort, and if I think there are long term positive changes that will allow the rider to tolerate a more traditional position, then I often make allowances - and prescribe some cycling specific off-the-bike exercises.  I don’t like to fit to dysfunction as a permanent solution if I have a pretty good idea that dysfunction can be corrected and improved.

During a session I might add spacer value to the stem in response to positive feedback, but I also counsel my clients that, in the long term, practicing some of the postural exercises I recommend will allow them to feel more relaxed in a lower position, obviating the need for that higher handlebar position.  An initial bike fit for new rider or dysfunctional one needs to be set up for immediate comfort, but also for long term positive adaptation. Bike fit should be a process, not an event.

Accommodation is bi-directional, and I like to use the marriage analogy.  You have a relationship with your bike that hopefully grows, adapts and ultimately flourishes, and, like a marriage, it takes some measure of accommodation from each partner.