How I Fit Athletes On Bikes
Bicycle fitting has come a very long way. I remember the days where someone would use a thumb and eye you up and down and say, here's your bike! Enjoy! Each process had to start somewhere, and most of us have had the experience, even I. Now-a-days bike fitting has become a healthy balance of science and art. That is what we try to bring to our athletes here when we fit them on their current bike, or for a new bike.
I've had so many people in recent months as me about our fit process and exactly how does it work? Let me give some detail on that, why we are different and do what we do.
Before I get into the fit portion, I will provide you with some of my background as a bike fitter. I have been in the biomechanic and exercise physiology field for many years and carry two degrees in the field. I have spent thousands upon thousands of hours watching athletes and their movement patterns, on equipment, throwing equipment, etc. Understanding how the muscles work together and create flawless motion has been my strength and moving an athlete out of pain or performing better. I started fitting cyclists and triathletes on bikes sometime back in 2007. It was a time where I took my past experiences and strengthened my cycling knowledge to start fitting athletes on bikes. Sometime in 2008, I was approached by Guru Cycles (from Montreal Canada) to become a fitter in the field for their line of bikes as they were looking to bring someone in that had an exercise science background. I was privy to the Dynamic Fit Unit (now the Guru Experience) years before it was available to the public. That was a turning point in my bike fitting career. I have recently completed my basic fit training with Dan Empfield at F.I.S.T. Basic Fit Camp, and will be heading out to California again (this February 2014) to F.I.S.T. Down Deep for an intensive training environment designed to hone the skills top fitters demonstrate.
Professional Dynamic Fit
I start each fit (whether a re-fit or a new fit) on our Dynamic Fit Unit (DFU). This mechanical ride is movable while you ride by the use of electronic motors. I have the ability to move you in the X and Y planes by the millimeter. Millimeters can mean the difference between comfort and discomfort, a rub spot or not and 10 more watts or no change. In reality, you are fitting yourself. I listen to you, move you in certain ranges and positions then take measurements and direct you down the right path based on your comments and reactions.
Once we (the athlete and I) have determined a primary position, the computer will spit out an XY, as well as the ability to take many other measurements such as bottom bracket to top of saddle height, nose of saddle to trough (hoods) distance, and more. Two scenarios can play out with these, and I will describe them both.
Scenario One - New Bike
I can use all this information for a new bike. From the DFU I receive a Saddle X/Y and a Handlebar X/Y. I turn to Slowtwich.com and use their bar to ht calculator. Based on the rider and their goals, I enter in proper head tube angle (road vs tri bike), stem length, stem pitch, spacer stack, etc. On the output end, I receive a stack and reach. Stack and reach has been confused among many athletes. A person does not have a stack and reach. The bike does. The stack and reach is for the bike frame. It is based off the bottom bracket center, up and forward (stack and reach).
Once the output gives me a stack and reach, I can look at bike frames that will provide the right geometry for the front end that suite the athlete the best. When going down this route, it starts to clear out what bikes will work or not. For example, I have someone right now who really wants a bike brand we carry, and no matter what, the front end I enter into the calculator with their XY coordinates, no front end combination will allow that rider to be in the position of choice. So, we took what could happen to make that bike work, put the athlete in that position on the DFU, and that athlete shook their head and said they could never ride in that position. The stack on the bike frame was too low (or aggressive) and there would have to be 60+ mm of spacers added to the steer tube (to get the athlete in the ballpark), which would make the bike ride horrible, be unstable and unsafe. It all comes down to what position is the most beneficial for the athlete; they feel comfortable and are able to perform to the level they know they can. It seems impossible to force an athlete in a position just because he/she wants a certain bike brand, however, I see it every day.
If you really want those pair of Levi Jeans, and no matter what size or shape you try, they just don't cut it. So why buy them? You would buy the pair of jeans that feel the best so you can move around in them freely while looking great!
Scenario Two -
Half my time is also spent helping athletes be re-fit on their current bike. It can be scary for me, as well as the athlete, because if they were not fit before they purchased their bike, they may hear the words they don't want to hear, "This bike is too big/small for you". I would say about 60% of the time the bike is the correct size, just not set up very well for the athlete. This is where the fit on the DFU is very helpful. I will fit the athlete first. Once we have that position, I can enter their current position, hit "go" and they move to their current set-up. We can move back and forth from good and bad so the athlete feels and sees the difference.
For those who have correct bike frames, but just set-up poorly, it is only a matter of taking bike measurements from the DFU and applying them to the bike. Sometimes it does require part changes, such as a seatposts, stem, handlebar, crank arms or all the above. Those are easy issues to solve.
For those who have the wrong sizes, it can become tougher. My goal with each bike fit is like throwing a dart at a dart board. I want to hit the center bullseye for maximum points. However, there is room to wiggle in the center that is ideal. When a bike frame is too big or too small, the best I can get is the ring just outside the center of the bullseye. The new position is better than the old one, however it may be 85-90% as good as it can be. Either the bike frame will not allow the position to occur, or I cannot make it happen to keep the integrity of the front end of the bike be stable, strong, steer well, be safe to ride and perform well.
More Than X/Y -
During each fit, I always address biomechanical issues and solve them. Many come in with a pain or injury and I want to ensure that the new position will begin to solve the issues. I want to give them "homework" to correct any poor movement patterns that are associated with their pain/injury. I also go through proper pedal stroke, spin scan and muscle balance performance with my fits. If you are not moving properly in space or cycling properly, the fit will never be complete or feel 100%. I strongly believe this is the crucial finish to complete the process.
Take Home Message -
My take home message is simple. Get Fit First. Period. If you have a bike and have not been fit or are not comfortable, get fit. It's going to be the best bang for your buck and give you the best results. The experience we provide with our re-fit and new bike fit is all about personalization and education. We want you to be the best you can be with the time you have and learn as much as possible.
Don't be scared by this. I see newbies to the sport and veterans of 30 years come in for a fit. You don't have to have a lick of experience to be fit. You deserve it and you are worth it!