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Another knee question

 
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PostPosted: Mon Apr 25, 2005 8:38 am GMT +0000    Post subject: Another knee question Reply with quote

Doc,

When I do my road training, usually at about mile 10 to 15, the top of my left knee starts to hurt. I've tried raising and lowering the seat, including of moving the seat foward and back. I've decided to experiment with the cleat position. What is the possible problem.

Thanks.
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The Bike Doc
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Location: Corpus Christi and Warda, Texas

PostPosted: Mon Apr 25, 2005 10:27 am GMT +0000    Post subject: Reply with quote

c0okie:

"Originality is the ability to hide your source." (Hondo Crouch)

I won't hide my sources on this one.

Lennard Zinn has an interesting discussion on cleat position and leg length discrepancy. Go to http://www.velonews.com/tech/report/articles/7212.0.html and go down to the middle of the page for his discussion.

Some general referencing points for location of pain may be helpful for you.

Pain in front of knee: Seat too low, too forward or cranks too long making knees overly flex at top dead center; too much big gear mashing

Pain inside of knee: toes point out too much; too much float in pedals; feet too far appart to each other

Pain in outside of knee: toes point in too much; too much float in pedals; feet too close to each other

Pain in back of knee: Seat too high or too far back; too much float in pedals

(Source Bicycling Medicine by Arnie Baker 1995)

Thanks,
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Paul K. Nolan, MD
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PostPosted: Wed May 11, 2005 10:17 am GMT +0000    Post subject: Reply with quote

Hey Doc

> Pain in front of knee: Seat too low, too forward or cranks too long making knees overly flex at top dead center; too much big gear mashing

I think this is me. My right kneecap gets pretty sore during riding. RBM fitted me on my bike and said my seat was too high, so they lowered it. I try not to mash big gears and try to spin.

Any other ideas? Thanks in advance.
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The Bike Doc
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PostPosted: Thu May 12, 2005 9:55 am GMT +0000    Post subject: Reply with quote

Guest:

After adjusting your seat so that you only have about 10 degrees of flexion for road riding 15 degrees for off road riding, if you find you are still having pain to the front of your knee, consider going with shorter cranks. Drop down 5 to 10 mm in crank size. Most mountain bikes come with generic 175 mm and road bikes with 172.5 or 170mm long cranks.

Thanks,
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PostPosted: Tue Feb 21, 2006 2:43 pm GMT +0000    Post subject: recovery for these old knees Reply with quote

Doc: I bought a new road bike and set it up according to the book. Took it out on a too-long ride about a month ago and have suffered from patellar pain since. Exacerbated by spinning, stairs, bending, etc. My question is now what? I can't stop riding but am I going to heal? Any suggestions? Crying or Very sad
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The Bike Doc
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PostPosted: Wed Feb 22, 2006 10:00 am GMT +0000    Post subject: Reply with quote

Pam:

Since you mentioned your bike was set up correctly, I will assume then that the seat is not too low or too far forward which can be sources of anterior knee pain. I will make some assumptions then based on the typical set up of a road bike. Did your road bike have a double chainring set up on the front? If so, swap it out for a tripple chainring set up. This will require a new bottom bracket and long cage rear derailleur to accomadate the new crank and greater chain slack that will result when you are on the inner chainring. If your road bike has a tripple chainring up front, look at swapping out the "road" cassette (typically a 12-23 or 12-25 cog range) on the rear to a more knee friendly 12-30 or 12-32. You will need to add more links to your chain due to the larger rear cog. Another option is to switch the front chainrings to a more "compact drive" set up on a double chainring crank switching from the typical 52 tooth large chain ring to a 48 tooth and a small chainring from a typical 42 to a 36. Also on the back switch out the rear cassette to the above described set up. This will require less cash out lay and still give you a fairly knee friendly set up. You still may want to change your crank set out from the typical 170mm length on road bikes to a more knee friendly 165 or even 155 mm crank arm length. This requires less bending of the knee when you are at the top of your stroke and can make it easier to pedal at a higher cadence.

The goal of these changes is to raise your RPM (cadence) of your pedalling and to avoid mashing big gears to make it easier on your knees. Shoot for cadences in the 90 to 110 RPM range. Since you want to stay on the bike, go easy on the intensity and the miles. A good rule of thumb is do not crank up your miles or intensity by more than 10% each week. Also, keep in mind that equal miles in different conditions are not equal intensities. Just remember days when you road with a tail wind to start and finished with a head wind. You road the same milage each way but the back loop was far more intense due to the head wind. Same goes with hills. Ease off on the hills for a couple of weeks to help your knees heal.

Consider a course of Glucosamine if you are not allergic to sulfa drugs or shell fish and are not taking Coumadin. The usual dose is 500mg three times a day or 1500mg once a day. I would recommend starting at 500 mg three times a day to make sure you tolerate it. Additionally, Chondroitin may be of some benefit with the same precautions for Glucosamine. The dose of Chondroitin is 200-400mg two the three times a day. Both supplements are commonly available in a fixed combination of 500mg Glucosamine and 400mg Chondroitin. You will need to take them for 6-8 weeks to realize the full benefit. They may help speed the healing and rebuilding of the knee cartilage.

Thanks,
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The Bike Doc
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Location: Corpus Christi and Warda, Texas

PostPosted: Thu Feb 23, 2006 5:47 am GMT +0000    Post subject: Reply with quote

Bump
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PostPosted: Thu Feb 23, 2006 9:37 am GMT +0000    Post subject: Reply with quote

Good thread doc.


.
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