Commuting - Knee pain/seat adjustment

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badger_bike
05-07-06, 06:02 AM
I've been commuting/biking regularly (on a mostly daily basis) for a while ... through the fall and winter ... but I'm still being stymied by knee pain. It's like an arc above the kneecap, and coming down inside the knee on both sides, and it's so bad sometimes that I actually need to stop and cringe for a bit. Mostly I've been ascribing it to just not being in great shape. I did try raising my seat, and that worked a little, but it's still pretty bad and I'm not sure otherwise how to adjust. My bike is a specialized hardrock I think 1999 (but possibly 1998). I've grown maybe 2 or 3 inches since then, but I can't imagine that's enough to really make a difference.
Help? :(
-Badger
sentinel4675
05-07-06, 06:12 AM
Have you been checked by a doctor to make sure there isn't something more serious like arthritis or a knee problem?
badger_bike
05-07-06, 06:32 AM
Have you been checked by a doctor to make sure there isn't something more serious like arthritis or a knee problem?
I hadn't; I actually hadn't considered arthritis or another problem because I'm quite young.
The first thing to check is fit, in particular seat height and fore/aft adjustment.
It could also be a problem with pedalling action. Are you mashing a tall gear? Gearing down so that you're spinning an easier gear is good for the knees.
What kind of pedals are you using? Could be a cleat adjustment problem. Can't think of the right term for it, but it may be due to your foot not coming down square on the pedal, which may be able to be fixed with an insert in your shoe to angle your foot to correct it.
donnamb
05-07-06, 02:23 PM
A 2-3 inch growth spurt could be just enough to cause you problems. My 2 inch spurt at age 17 made me have to get a brand new bike. It just didn't work, no matter how many adjustments made. Do you have a LBS where you are that has someone good at troubleshooting these things?
I agree, first check the fit.
Also check your pedaling technique. What is your usual cadence when riding? If you're using gears that are too hard for your fitness level, you put a lot of extra strain on your knees.
Ricardo
05-07-06, 03:29 PM
Sounds like a case of condromalacia. Visit your doc.
Ricardo
cgchambers
05-07-06, 04:29 PM
I have had similar problems, and am not sure exactly what it is either. I switched my pedals, and that seemed to work. Do you use clips? I used Shimano SPD's at first, but not having any float really effected my knees. I switched to Speedplay pedals, and my knee pain went away. Hope this helps, worked for me. :)
badger_bike
05-07-06, 07:36 PM
The first thing to check is fit, in particular seat height and fore/aft adjustment.
It could also be a problem with pedalling action. Are you mashing a tall gear? Gearing down so that you're spinning an easier gear is good for the knees.
What kind of pedals are you using? Could be a cleat adjustment problem. Can't think of the right term for it, but it may be due to your foot not coming down square on the pedal, which may be able to be fixed with an insert in your shoe to angle your foot to correct it.
Like I said I've tried raising the seat (... I don't think it goes up any higher, actually). How would I adjust it fore/aft?
I try to pedal at a comfortable gear (I think the derailleur may need readjustment again); the lower gears feel like I'm spinning way too fast and actually hurt more I think because my knees are bending more.
However: I am quite flat-footed, could that be part of the problem?
badger_bike
05-07-06, 07:51 PM
I agree, first check the fit.
Also check your pedaling technique. What is your usual cadence when riding? If you're using gears that are too hard for your fitness level, you put a lot of extra strain on your knees.
I pedal at a moderate pace; when I use lower gears it feels like I'm pedaling *too* fast, and the rapid bending/unbending makes me hurt faster than the higher gears will.
HiYoSilver
05-08-06, 08:50 AM
You may need PT. See your Dr to give you an appointment. You don't want to wreck your legs because it's just a bit of pain. You definitely need to have your bike fitted. If not sure and don't want to google, then go to a good LBS and get a fit. Even $100 is a cheap price for knees. Mashing, i.e. powering at low rpm's, is hard on the knees. A good goal is 85 to 95 rpm's. But it takes about 3-5 days to get used to spinning this fast. The typical low speed rpm is about 70 is more efficient but at a cost of harder on the kness. Higher rpm is much easier on the knees but will leave you gasping for breathe and you'll swear you can't move your legs that fast until you train the muscles. Easiest way to increase rpm, i.e. cadence, is to peddle fast for about 30 seconds, rest and pedal slower, repeat 5 times. Do that for 5 days and you should find it easier to pedal faster.
chromedome
05-08-06, 09:07 AM
The standard method of checking seat height and position is this:
1) Find your true inseam length by pushing a tape measure into your crotch to the point of bone that you sit on when you're on your bike, then (standing upright barefoot) measure to the floor. Multiply by 0.89. Thats the height of your saddle (the point that you sit) from your bottom bracket spindle.
2) With your seat adjusted to that height, sit on it, leaning against the wall or a friend, and put your feet in the pedals. Put one foot at bottom dead center. (Your knee should be bent 15 degrees at that point,) then drop a plumb line from the front edge of your knee cap. The line should go right through the ball of your foot, if you are sitting in the place of your saddle that you would normally sit. Adjsut your saddle forward or backward so that it does. (Maybe forward.)
3) After you have your saddle at the proper height and position, try it for about 2-4 weeks. Then when you adjust, just make little (2-4mm) adjustments at a time.
4) If you are riding on the road, ride at a cadence of about 90. Sometimes when we ride at a slower cadence we're using too high of a gear, making our knees work too hard. A slightly lower gear with a higher cadence is a little easier on our knees, and more efficient.
5) Have fun.
Adjusting the fore/aft position of the seat involves loosening the retainer under the saddle and sliding it along the seat rails. Common wisdom is that your knee is directly over the pedal spindle when the pedal is at the 3 o'clock position. Don't take this as an absolute, but it's a good starting place to find your best position.
You say pedaling faster makes it worse because of the rapid bending and unbending of your knees. This makes me think your seat is way too low. A good seat height will give you the minimum amount of knee bending. I'm wondering if your bike is simply too small for you to achieve a good fit.
badger_bike
05-08-06, 02:22 PM
Thank you all for the replies so far :)
I actually went to my LBS today; I asked them about the problem and was actually told that I have the seat up so high that there's too little of the post in the frame itself. The basic options I was given were to get a longer seatpost, or look into getting a bike that's bigger. The former I can afford, the latter I can't, although my family still has my older brother's cannondale, of about the same year as my bike (might be more like 2000), which might work out better for me. I won't be able to test that option for another week or so, though, because the cannondale is at my home in Newton.
Aaron Cormack
05-08-06, 04:18 PM
Hi badger
I am not too experienced - hopefully others will chime in here - but I have to say that I can't see how (providing the seat post is solidly secured to the frame) that 'too little of the post is in the frame itself' (I realise this is your quote, not theres) is causing the problem with your knee.
If your local bike shop is saying the seat needs raising to make it fit properly, or they are saying the seat post needs replacing because it really is unsafe, then fair enough...
Please feel free to correct me anyone!
badger_bike
05-08-06, 04:30 PM
Hi badger
I am not too experienced - hopefully others will chime in here - but I have to say that I can't see how (providing the seat post is solidly secured to the frame) that 'too little of the post is in the frame itself' (I realise this is your quote, not theres) is causing the problem with your knee.
If your local bike shop is saying the seat needs raising to make it fit properly, or they are saying the seat post needs replacing because it really is unsafe, then fair enough...
What they meant I believe is that if I'm still having knee pain the way I am, then the post is not high enough, and the bike is still ill-fitting. What they meant about the post height was... it's hard to explain, but google gives me:
"While we are on the subject of marks stamped on the post, there is another marking on all seatposts, a line with the words "max height" near it, as kind of a hedge against liability suits. This line marks the point above which it is unsafe to raise your seatpost. It is generally between 65mm and 80mm from the physical bottom of the seatpost. Each post is made of different materials, different aluminum or steel alloys, that have a particular shear strength for that material, in that thickness. This shear strength is taken into account as the "max height" is developed for each seatpost. It is based on the likelihood of failure from a forward or rearward motion with body weight on top. The Maximum Height marking provides for a safe amount of seatpost in the frame, to both support the seat tube stress and to anchor the post against the rider merely shearing off the post, accidentally, in abusive use."
The seatpost on my bike is raised past that line, and thus isn't stable, and yet it still isn't high enough for me to be comfortable. Hence, the recommendation of a longer seatpost, so I can make the seat higher, but not risk damage to me/the bike. At least this is how I understand it to be. So essentially yes, they are saying the seatpost needs replacing because where I have it is unsafe.
Aaron Cormack
05-08-06, 04:35 PM
Badger
Ok - sounds fair enough to me then...!
[edited to say - it is just that the nearest bike shop to me would say stuff like that to me (when it turns out that wasn't the problem)... It took me a while and a fair amount of money before I realised / wouldn't want to see anyone have that. Luckily found another nearby which is fine...]
joejack951
05-08-06, 04:45 PM
Keep in mind that raising the seat post much higher may also necessitate raising the handlebars to compensate. How tall are you and what size is the frame you are currently riding? I've read it on this site and elsewhere (and it also seems to work for me) that a quick way to set the seat height is to raise it until you can just reach the pedal with your heel and your knee fully locked out. With my seats set using that method, I've only had to make very minor adjustments and those are probably due to my unequal length legs.
badger_bike
05-08-06, 05:01 PM
Badger
Ok - sounds fair enough to me then...!
[edited to say - it is just that the nearest bike shop to me would say stuff like that to me (when it turns out that wasn't the problem)... It took me a while and a fair amount of money before I realised / wouldn't want to see anyone have that. Luckily found another nearby which is fine...]
Understandable. :) I've gone to them before and they've given me good advice and been quite trustworthy.
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