Bike Fitting and Back/Pelvic Muscles

[makbike]

I saw a professional bike fitter back in December. He spent nearly 2.5 hours adjusting things on my bike to make it more comfortable. Since I have one leg shorter than the other he tried to find a happy median for the saddle height. Here are the changes he made:

Saddle height was 65 cm he changed it to 66

Drop (saddle to bars) 2 cm to 3.5 cm

Nose to bars 45 cm to 44 cm

Nose to hoods 61 cm to 58 cm

Saddle setback 5 to 4

After the fitting I had my bike on my trainer all of January and Feburary (too cold to ride outside). In March I started riding on the road and I noticed my lower back (lumbar region and sacrum) was tight. The tightness then started to girdle me, that is go around to my anterior pelvic region. I saw my chiropractor and utilized the student massage client for several treatments/adjustments/massages and had a lot of relief. However, the pain is back and is now accompanied with spasms in my lower back. I had yet another massage Monday evening and the student focused on my psoas muscles and lower back. I felt great when I left. However, I'm a teacher and spend a majority of my day on my feet. After about 3 hours of being on my feet Tuesday morning my back and pelvis were yelling at me. I do get some relief when I sit and a lot after I ride. I rode hard last night and afterwards my lower back went into spasms. I'm seeing a new chiropractor in town tomorrow (I loved the ones I was seeing but they are 25 miles away and with my current teaching/tutoring schedule it is not possible for me to get to their office).

Here is my question - is it possible that the adjustments made to my bike back in December are contributing to my on going muscle issues? I'm wondering with the changes made if the change in my hip angle simply has me using muscles in a different way and they are not appreciative of the new work. I'm open to any suggestions or ideas you gals may have for I simply want to be pain free.

Thanks!

[aicabsolut]

Hey,
See Mr. Silver's LCL thread for a link to an article I posted on pelvic symmetry and cycling. Also check out cyclingnews.com 's Fitness Q&As. Steve Hogg (supposedly one of the best bike fitters) has a lot of info on functional and measurable leg length discrepancies and what to do about them.

Have you ever tried any shims under the short leg? Finding some compromise position means you're still stretching too far with one leg and now you've also hindered the performance of the long one. Some people even try 2 different crank arms.

[Triskeliongirl]

I have a 3 cm leg length discrepancy, and I had exactly the pain you describe until my bike was fit to correct for the problem. Because my LLD is so large, I had to get a custom crank set from tom slocum at high sierra cycling. It features a dropped pedal on my long leg side, and elliptical off set chain rings to balance the leverage throughout the pedal stroke. If you didn't have this pain before you bike was adjusted, you could try putting the handlebars back up like they were before, 3.5 cm is a big drop.

[velogirl]

Lower back pain is typically caused by tight hamstrings. From a fitting POV, increasing the drop between your saddle and bar could contribute to this pain. While 3.5cm isn't terribly aggressive for a 20-something racer, it's unusual for a recreational rider. You could add a stem with a greater degree of rise to ease the lower back issue.

How significant is your leg length discrepency? Do you know if if it's dynamic/functional (ie caused by variable flexibility in your hip joints) or if it's a bone length discrepency? If bone length, tibia or femur? The answer to these questions will determine if you need correction and which method will work best for you. A discrepency of 1-2cm doesn't necessarily need to be corrected -- your body will compensate for it. More than 2cm is considered significant and should be corrected. The most common lld is dynamic or femur, both which are corrected by cleat positioning (you fit your saddle height for the shorter leg and then move the cleat on the longer leg back to increase your extension). Less common is tibia, corrected by shims. Variable length cranks are extremely unusual as correction for only the most significant discrepencies.

Hope this helps!