|Body position on a bicycle has become a studied science, blended with art and experience. Dr. Andy Pruitt has been actively fitting people on bicycles, treating the injuries caused by faulty bike fit, and trying to make a science of it all for thirty years. Still today, at his practice at the Boulder Center for Sports Medicine, He continues to learn daily. He doesn’t follow vogue trends based on limited experience. He applies and teaches fitting techniques learned and developed during the course of large numbers of repetitions. He shares his expertise openly through clinics, seminars, books, and now the Body Geometry Fit School because he knows the value of proper fit: It improves real people’s lives.
Cyclists are often obsessed with bike fit. The more experienced they become, the more they worry about the subtle differences that a couple of millimeters can make. Eddy Merckx, probably the greatest cyclist who ever lived, always carried a five-millimeter Allen key in his jersey pocket. He was famous for making slight adjustments in saddle height several times per day, even during races. It is often said that Merckx was persnickety about bicycle fit because he suffered nagging pain from injuries in a crash. However, he also had an undetected physical anomaly that gave him problems during his whole career.
A few years ago, Eddy brought his son Axel to Dr. Pruitt's office. Axel was a successful pro in his own right. When Dr. Pruitt examined the young rider he found a significant leg length inequality, primarily in his femur (or thigh bone). He then discovered the same condition with Eddy. Once this diagnosis was made, Eddy knew why he had been so uncomfortable on the bike all those years. At the thought of all the pain he had suffered, pain that could have been alleviated with a properly shimmed and adjusted cleat, he remarked with his characteristic rueful grin: “Where were you when I was riding?”
Merckx’s perpetual saddle height adjustment points out two things all cyclists come to learn. First, if you are uncomfortable, riding is no fun. Secondly, proper fit is critical for maximum efficiency, and no one wants to squander even one hard earned watt due to inappropriate bicycle fit. Fortunately, it is not hard to help people find a near ideal position. Over the years, Dr. Pruitt has developed four basic rules for bike fit:
• Bike fit is a marriage between the bicycle and the rider.
• Make the bike fit the body; don’t make the body fit the bike.
• Dynamic bike fit is better than static bike fit.
• Cycling is a sport of repetition.
Rule #1 Bike fit is a marriage between the bicycle and the rider. If the two are incompatible, the marriage will fail. There is an important qualifier to this rule. The bike can be adjusted to the rider’s anatomy in multiple ways, such as moving the saddle up or down or changing the stem. The body can be adjusted only in minor ways, such as with a carefully designed stretching program. This leads us to the second rule.
Rule #2 Make the bike fit the body; don’t make the body fit the bike. It is easy to adjust the bike, but difficult to stretch or contort the body into some preconceived “ideal” or “pro” position. For example, long legs coupled with a short torso and arms require a bike with a relatively short top tube/stem combination, which is referred to as reach. Stubby legs and most of the height in the torso requires a bike with a long top tube and stem. Forget what your favorite pro rider looks like…unless their body is a carbon copy of yours (which it’s not). Make your bike reflect you, not your hero.
Rule #3 Dynamic bike fit is better than static bike fit. This means that fit while pedaling the bike needs to be considered when fine-tuning such things as saddle height and cleat position. Static formulas for deciding saddle height are only starting points. They must be overruled with dynamic findings, such as observing the rider on a trainer. A pedaling rider is constantly moving on the bike. A rider actually rises slightly from the saddle with every down stroke. So, ideal saddle height is different when one is pedaling compared to just sitting motionless. The degree of ankling (how much the ankle articulates through the pedal stroke) also plays a role in saddle height. To complicate things even more, terrain often changes a rider’s ankling patterns. At the Boulder Center for Sports Medicine, we use a computerized three-dimensional motion capture system to dynamically capture riders at a variety of workloads. This is the most accurate way to determine appropriate saddle height, but is inappropriate for bike shops, homes or even most medical offices. However, riding at different cadences and loads on a trainer can provide insight to an individual’s pedal stroke in different situations.
There is nothing wrong with static bike fit formulas as a starting place. But for a proper fit, it is critical to observe the rider while pedaling. It is also imperative that you learn when a particular subject’s bike fit issues are beyond correction in anything other than a full medical setting.
Rule #4Cycling is a sport of repetition. A cadence of 90 revolutions per minute is approximately 5000 revolutions per hour. A six-hour century would require 30,000 pedal revolutions. Every pedal stroke is almost identical, so it needs to be in the safest position to allow for this kind of repetitive activity. A saddle that is five millimeters too low on a six-hour century can lead to major knee pain problems over that time. Because of this, the most important bike fit for a cyclist is the first one, to assure a long, comfortable, healthy cycling career.
It should be noted that our bodies change on a regular basis; therefore, bike fit is not static in its nature, but is dynamic throughout our cycling lives. My position today is significantly different than it was when I was an elite 30-year-old racer. This would ring true for anyone’s long cycling career. We should not expect the novice cyclist beginning their cycling career at middle age to be able to perform comfortably in an aggressive race position. Many people are entering cycling as a sport on the heels of an injury from another sport, and those injuries need to be addressed in their position on the bike.
Once you understand these four rules and reasons, you will begin to see how BG FIT uniquely caters to the cyclist’s individual attributes to maximize their comfort and performance on the bike.
For more information and to watch a video of Andy Schleck getting BG FIT by Dr. Andy Pruitt the Saxo Training Camp in Mallorca, Spain...go here.