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Project Pruitt: The Fit Session
Tom LeCarner gets fit by the pros — the video shows dramatic improvement, but will it get him riding pain-free again?
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It was a crisp fall day here in Boulder as I pulled up to the Boulder Center for Sports Medicine with my bike on my car and all my gear in a bag. I was swiftly directed to the locker room and changed into my kit while my bike was rolled away to the fit lab by a staff member for “calibration.”
I was then brought into the biomechanical fit lab, which was impressive, and, frankly, a bit intimidating. When I walked in, my bike was already there in the center of the room, mounted to a trainer, which was hooked up to a remote unit that controlled the wattage output.
The bike was surrounded on all sides by floor-to-ceiling black curtains. An aluminum frame apparatus was built into the ceiling; it looked a bit like a photo studio for some high-fashion magazine. Mounted all around the bike were six infrared cameras with black lenses and red LED lights that looked like something out of the Transformers movie. There was also a digital video camera to capture video images from the side of the bike. One of the walls had dozens of saddles, stems, shoe inserts, and sundry other bike parts.
Pruitt introduced me to Sean Madsen, a biomechanics expert and the chief bike fitter for BCSM. He asked me to put my old shoes on (Sidi Ergo II carbon), and hop on my bike to warm up for about 10 minutes. As I was warming up, both Pruitt and Sean were observing me, making comments to each other and, of course, nodding a lot. It was time to see how my custom-made bike actually fit me.
As a bit of background on my bike; it is an Independent Fabrication Ti Crown Jewel. I purchased it two years ago and it was made according to a fit that I had done here in Boulder. I rode it for a year and a half without any complaints at all; it’s a dream bike. When I first started having symptoms back in April of this year, I had some minor adjustments made with my fitter. The adjustments that were made, according to Pruitt, were in the right direction, but were simply not enough. I was still in pain even on the mellowest rides.
After my warm-up, I was ready for the first “data capture,” which is when the cameras start rolling and recording my pedal stroke and position on the bike. I was fitted with “anatomical landmarks,” which are tiny EPCOT-looking bubbles that reflect the light from the infrared cameras; these were attached to my hips, knees, ankles, heels and toes and track my body parts as I pedal. It’s the same technology used in films like Lord of the Rings to create creatures like Golum; it was totally cool.
I pedaled at 275 watts at 80 rpm for about 2-3 minutes and the data capture was complete. I continued pedaling and waited while Andy and Sean analyzed the data on the computer on the other side of the black curtain.
They told me to come have a look. On the screen was all of my personal information and all of the data that the cameras just captured. The data showed some alarming things about my position on the bike.
Before
If you look at Figure 1, you will see my initial riding position. It certainly isn’t terrible, and both Madsen and Pruitt acknowledged that they had seen much worse.
Figure 2 however, indicates where my problems are coming from. The red and green lines represent animated versions of my right and left leg respectively. The red and black arcs are the paths made by my knees; they are supposed to be overlapping, or at the very least, much closer together. As you can see, they are not; my right knee is much farther out in its path from the left. The image is even more striking when you look at my knees from the front, which is shown in Figure 3.
The red is, again, my right and the black my left. The knees are making what Pruitt referred to as “reverse parentheses” in their path, which is not optimal. The right knee, at the very bottom of the pedal stroke, curves out, which puts tremendous strain on the pes ansurinus tendons that stretch from the back of the leg, around the inside of the knee and attach toward the front. This is precisely where my pain is coming from.
Figure 4, the view from the from the top, shows the same thing, but also indicates that my left knee is even worse than my right; so much so that Pruitt found it amazing that my left knee wasn’t bothering me as well—he indicated that it might have sooner or later. The two little blue lines at the bottom of Figure 4 show what is called hip rock; the less hip rock the more efficient the pedal stroke. The “normative value” for hip rock is .005-.020, mine was .073, not good.
The overall picture of this first data capture indicates that my knees are all over the place, which is causing the pain. It also shows that my hips are clearly moving too much, due to the fact that my saddle is too far back.
After
After the analysis, adjustments were made to my bike, including a 1.5cm forward adjustment of the saddle and lifting my handlebars by about .5cm. Madsen told me that he normally “deals in millimeters” so moving my saddle forward by 1.5cm is essentially a mile in bike fit parlance. In addition to the bike adjustments, I was fitted with a pair of Specialized Body Geometry shoes with the blue BG inserts. The shoes were fitted with an arch capture and a varus support, which were both critical in correcting my dynamic knee alignment.
The second data capture revealed a marked improvement in my position on the bike. The photo in Figure 5 shows my position from the side after the adjustments. You can see that my back is straighter, my head is more upright and there is still a good bend at the shoulders and elbows.
When we looked at the animated version, we saw an enormous difference. In Figure 6 you can see the side view of my knees, which, while still not perfectly overlapping, are significantly closer together. In Figure 7, from the front, you can see that the “reverse parentheses” is virtually eliminated, and it is particularly noticeable on the left knee.
Figure 8, from above, shows the same improvement, again with dramatic progress on the left knee, and the right knee tracks nearly perfectly up and down and the hip rock is all but gone, which, according to Pruitt should provide some improved power output due to increased pedaling efficiency—a nice side effect.
Overall, the fit experience taught me a number of things. First, even if you do everything “right,” as I did, buying a custom bike, having a carefully measured fit, etc., things can still go wrong. For the majority of riders, a professional bike fitter will provide you with optimal positioning that will give you years of pain-free, efficient riding. But remember, the fit system is only as good as the fitter who uses it, so choose wisely; consult your friends, ask questions and interview your fitter about his or her philosophy on bike fitting before you plunk down $200-$300 for a fit. There are, however, some of us who need an extra step. We need a more medically based approach to bike fitting, for a variety of reasons.
Second, I learned that millimeters and centimeters on a bicycle can make a huge difference. You’ve seen ads for bikes that fit people “from 5’8” to 6’0”” which is a bunch of crap. Even if you are “normally” proportioned as I am (5’11” 172lbs), you need to make sure that your bike fits you, not some generic human with similar measurements. Our bodies all have idiosyncrasies, many of which we are unaware; I have extremely tight hamstrings and this affects the way I sit on the bike. A bike fitter who understands the fundamentals of biomechanics and the interrelationship between your body and your bike is essential for uncovering the individual limitations of your body.
Finally, Andy and Sean both explained to me that even though I am in a much better riding position and that my knees are doing what they’re supposed to be doing, a proper bike fit is not the “magic bullet” to my recovery, but is rather the first step. From here, I will be seeing a physical therapist at Boulder Center for Sports Medicine, Tami Dick, PT, who developed the Specialized Body Geometry physical assessment program. She will help me with increasing the flexibility in my hamstrings and glutes, as well as working on the knee itself. I will keep you posted on these sessions as they go.
Editor’s note:Tom LeCarner, VeloNews’ copy editor, is a 41-year-old longtime cyclist and former racer who has been struggling with tendonitis this year. Specialized has offered to help Tom overcome his injuries with its Body Geometry equipment and treatment by Andy Pruitt of the Boulder Center for Sports Medicine. Tom will report on if and how he progresses in a regular column on VeloNews.com.
Related
The video from the fit session 
