Knee pain from cycling

[Svend]

Perhaps someone can help me with this one...

Since I started riding this spring, my knees have been hurting.  Initially it was just for a day or two following a ride; and now it lasts longer....sometimes 3 or 4 days.  My bike is set up exactly the same as it was when I left it last autumn, so no changes there.  Although, I have recently started tweaking a few things to see if I can solve this -- moved the seat back about an inch; raised the seat 1/2 to 3/4 inch for long flat rides -- nothing has worked.

I am really wondering what is causing this.  Seat position still off? Crank length too short? Pedal cleat alignment, forcing my legs into an unnatural position? Or is it just a matter of too many miles too soon in the season, without a "break-in" period?

I have never had knee pain from anything, not even skiing.  Anyone have any insight?

Thanks in advance!

[jim-ratliff]

I think I said this wrong on an earlier post, but something I was reading recently said that when the pedals are horizontal, the lower leg above the pedal that is forward is vertical, and that if you are having knee pain (sort of under the kneecap) its because of those bad angles.


Raise your seat more or slide the seat farther back (or longer cranks).
One option, but do some "googling" of symptoms and see what comes back.

[midwif]

Hmmm, longer cranks?
Are you guys sure?

I've heard longer cranks, more torque on knees.
Not  knowledgeable enough argue about it though.

Svend,
where is the pain?

Inside/outside of knees?
On edge of knee caps?

Lynn

[jim-ratliff]

I don't imagine anyone is going to actually change the cranks on their bicycles, but larger frames typically have longer cranks and will sometimes have a greater seat tube angle -- aimed at reducing the knee angles.

The link below is a pretty good sounding article.  Given that the bike setup is static from last year, I would vote for putting too much muscle into pedaling by pushing too high gears.  Increase the cadence.  New shoes or pedals?



http://www.cptips.com/knee.htm

[Svend]

OK - checked out the crank length, and they seem to be as long as they come -- 175mm.  I don't think I can or want to change that.  The smaller frames for that bike came with 170mm cranks, so mine seem OK.

Hmmm, longer cranks?
Are you guys sure?

I've heard longer cranks, more torque on knees.

Right on, Lynn.  Jim's article link confirms that -- too long a crank = knee pain.  I thought it was the opposite...wrong.  But I don't suspect that is the problem.

Svend,
where is the pain?

Inside/outside of knees?
On edge of knee caps?

The pain is around the knee caps.  Not serious, but quite uncomfortable, and something I want to sort out before it gets debilitating and messes up my cycling and next ski season.

In reading that article (good one, BTW -- thanks Jim!) there are a couple of things discussed that I want to check out that may be at the root of this:

1) Check my knee orientation to pedal when in the 3:00 position; move seat back if needed;

2) Check my cleat orientation and how they position my feet fore-aft on the pedals, as well as lateral alignment; reposition cleats as needed (I will check Terryl's too, now that I have heightened awareness  ).  I know that my cleats are positioned rather far back on my shoes, and this may not be good.

I'll let you know what I find.....

I think I might have overdone it in the first couple of weeks, actually.  Too far, too soon, low cadence, pushing high gears.  Just too fired up to get back out on the trails, I guess.

Thanks for the help. You're the best!

[jim-ratliff]

My guess in bold.   

In reading that article (good one, BTW -- thanks Jim!) there are a couple of things I want to try that may be at the root of this:

1) Check my knee orientation to pedal when in the 3:00 position; move seat back if needed;

2) Check my cleat orientation and how they position my feet fore-aft on the pedals, as well as lateral alignment; reposition cleats as needed (I will check Terryl's too, now that I have heightened awareness  ).  I know that my cleats are positioned rather far back on my shoes, and this may not be good.

I think I might have overdone it in the first couple of weeks.  Too far, too soon, low cadence, pushing high gears.

Thanks for the help. You're the best!

[bushwacka]

Jim and you pretty much nailed it. to far, too soon at low of a cadence.

Crank lenght discusses. IF you guys read Leanord Zinn at all he found that most people would make more power with longer cranks as long your fit was no compromise. The problem is with most thing though we run shorter crank arms for clearance issue both with the frame, our body and and the ground. Shorter cranks will solve knee problem some of the time but I would first address your fit and riding styles before sacrificial power to get ride of pain.

The other thing I can add is standing every once in a while while climbing will take some of the stress of your knees. ...and dont become a cycling only athlete IE hike/jog/swim play basketball elect whatever to stop over use from cycling injuries. 

[LivingProof]

Svend,

Are you on a road bike or a 29'er, and, how long do you ride? Are you climbing?

I, too, am thinking you are going too hard/too long/too soon. Early in the season, I limit riding to an hour with no knee stress and it takes a while for my knees to acclimate. I've never had knee issues other than some minor tweaks. I returned from Colorado this season with some minor discomfort and cycling actually helped strengthen the knee. Just ride in easy gears and spin more. I use Harb's foot pull-back thought in the bottom half of my cycle to reduce the push-only power stroke used by untrained riders.

[jim-ratliff]

Svend:

FWIW, I've been having the same intermittent issues this spring, but only my right knee. Decided in my case that it was trying to do intervals of hard pedaling too frequently, usually by consciously selecting too high a gear when going uphill.  The goal was to build a bit of strength.

I also found that it is better to make sure I am warmed up before beginning to pedal harder, but I have now stopped most of that to give my knees and tendons a rest from the muscling. Back to higher cadence.  FWIW, Lynn says it takes much longer for tendons and bones to grow than muscles.

Still tring to catch up with Lynn in her hill country.

[Svend]

Sorry for the late reply folks.  I wanted to make some tweaks to the bike and get a solid ride in tonight before posting back.

But first some responses to some comments:

Are you on a road bike or a 29'er, and, how long do you ride? Are you climbing?

I, too, am thinking you are going too hard/too long/too soon. Early in the season, I limit riding to an hour with no knee stress and it takes a while for my knees to acclimate. I've never had knee issues other than some minor tweaks. I returned from Colorado this season with some minor discomfort and cycling actually helped strengthen the knee. Just ride in easy gears and spin more. I use Harb's foot pull-back thought in the bottom half of my cycle to reduce the push-only power stroke used by untrained riders.

Mike, I only have a 29er....no road bike (yet).  The riding this spring has been a mix of flat hard packed gravel rail trail, upon which I have been doing about 20 to 30 km per ride; as well as trails in the woods, which is pretty much constantly up and down hills....some long, gradual; some short, steep.  As for the pull on the upstroke, that is slowly getting burned into my cranium and becoming instinct.  Just like some ski moves don't come instinctively to me yet, neither has this way of pedaling.  I'll get there...... 

...and dont become a cycling only athlete IE hike/jog/swim play basketball elect whatever to stop over use from cycling injuries. 

BW -- yeah, I gotta do something different every now and then.  It's just that mountain biking is so darn fun    But, good advice.

OK, so I made some adjustments pre-ride and on-trail, and hit the flat rail trail tonight for an easy, no stress on the knees, one hour ride....about 25 km or so.  Here are the changes:

1) Lowered seat about 3/4 inch = good move; smoother pedaling; no more hip wobble; better tracking of front wheel (more stable steering) due to more balanced pedaling, less bike weave.

2) Moved seat back ~1 inch = good move; knees now just slightly forward of pedal axle; far more power; smoother pedaling; really noticeable reduction in stress on the knees.

3) Inclined seat more forward (just a titch) = good move; body weight sits more on pelvic bones, rather than soft tissue; allows hips to move more freely; smoother pedaling.

(FYI: I didn't do these all at once, but made one change after another, with about 20 min. riding in between, to see what the effect of each change was).

Finally, I checked this after the ride, and adjusted (won't know the effect until my next ride):
4) Moved shoe cleats to place foot further back on the pedal, so that ball of foot is directly over pedal axle; and moved cleats so that feet are more outboard.  Hope this helps too....    BTW, lateral alignment (toe-in / toe-out) was good.

So, it seems that the pain was perhaps caused by a combination of two factors:  some alignment/fit problems; and, as you all confirm, doing too much/too soon/too fast/ low cadence, plus stressing the knees on the hill climbs in too high a gear.  Yes Jim, I've done the same as you, thinking I was doing my body a favour, building strength and getting more exercise. 

It'll probably take some time for the inflammation to subside (hopefully not too long).  Time for a break from the bike, and play some soccer and football with the kids.   

Thanks all, for your advice.  Much appreciated! It's been a great help.

Cheers....

[midwif]

I've done the same as you, thinking I was doing my body a favour, building strength and getting more exercise.  It'll probably take some time for the inflammation to subside (hopefully not too long). Time to play some soccer and football with the kids.   

Thanks all, for your advice.  Much appreciated! It's been a great help.

Cheers....

Think the two I's.

-ICE
-Ibuprofen.

I recommend icing knees for 15 minutes after each ride. Ibuprofen after harder rides.

I too have sore knee caps at the beginning  of each riding season. Where the muscles attach to the knee cap on the top and bottom of my knee cap is where I feel it. I focus on lower resistance, higherturn over.

And despite what Jim says, I ain't much of a hill climber. I'm just persistent. Willing to go really, really slow and accept lactic acidosis.

L.

[Svend]

Think the two I's.

-ICE
-Ibuprofen.

I recommend icing knees for 15 minutes after each ride. Ibuprofen after harder rides.

How about Scotch? Single malt.  I will gladly self-prescribe! It relaxes my facial muscles nicely, so should do wonders for my sore knees 

I too have sore knee caps at the beginning  of each riding season. Where the muscles attach to the knee cap on the top and bottom of my knee cap is where I feel it. I focus on lower resistance, higherturn over.

Same place that mine hurt.  Hope it doesn't become chronic.  But will definitely take it easy on the high gears / low cadence thing.

Weird thing, this.....I can ski for 5, 6, 7 days straight, 4 to 6 hours a day, and not feel a twitch of pain in my knees.  But get on my bike a couple times, and Whammo.  But, then, if I actually bent my knees when I skied, I might actually feel something there 

[Svend]

I returned from Colorado this season with some minor discomfort and cycling actually helped strengthen the knee.

Mike -- cycling can be a remarkable healer, you're right.  It has helped both my wife and 12 year old daughter recover from surgery and injury.  After knee surgery to remove a damaged meniscus, my wife was ordered by her surgeon to get on her bike within 48 hours of the surgery, and keep doing that every 2 days.  It helped immensely to free up the joint and get the blood flowing.  And recently, our daughter sprained her foot in a soccer game, and cycling helped get her back onto the field in only 3 weeks.  Three times a week, 20 km each, ice cream at the trailside cafe at the halfway point     It was the perfect low-impact way to get the bones and ligaments moving and speed the healing.  It's just  great sport.  We all love it.

[jim-ratliff]

Hmmm, longer cranks?
Are you guys sure?

I've heard longer cranks, more torque on knees.
Not  knowledgeable enough argue about it though.

Lynn

Thought I would respond to Lynn's message, though I'm not knowledgeable enough to say much other than this.

Torque is twisting force, so crank length won't affect or createu any "twisting force" on the knee (unless your knees really flail around while you pedal).

 To go a given speed, it takes less force on the pedal as the crank gets longer.
For a given amount of pedal force, a longer crank will create more twisting force (torque) on the chain rings because torque is the result of force and lever arm.  (1 foot-pound of torgue is a 1 pound weight/force on a 1 foot lever arm.  If you keep the weight/force the same and increase the lever arm to 18", then you have a 50% increase to1.5 foot-pounds of torque).

However, increasing the crank arm also increases the diameter of the circle created by the pedal, with longer downstroke (for longer legs) but also a higher upstroke.  Slightly more forward pedal position but also slightly  more rearward on the back side of the pedal stroke.  A shorter legged person with a long crank will create more torque, but will also increase their range of motion requirements in the knees and hips (and that may be bad for the average person, not sure).

The pedal being forward is good for the knee angles of larger riders, helps get their BOF (Ball of Foot) more forward and under the COM (center of mass of the knee). 

If Lynn puts 75 pounds of force on her 170mm cranks, then she is creating 502 pound-inches of torque.
If Svend puts 75 pounds of force on his pedal with 175 mm cranks, then he creates 517 pound-inches of torque, a 3% increase in torque for a minimal 2.5 mm crank length change.
With a 200mm crank the torque goes up to a whopping 590.5 pound-inches with only the same 75 lbs on the pedal.

The pressure on the knee is the same, but the angle of the pressure on the knee might be different depending on leg length and stuff and that might be a big downside.  Note also, of course, that Lynn doesn't need to create as much torque because she isn't doing as much work since she only has to move 120 lbs compared to me.

FWIW, my Mtn Bike has 175 cranks, my road bike's are 172.5, and the authority that BushWacka referenced uses 203mm cranks (and did so when he raced professionally).   



PS.  But there's no "free lunch" in physics, so somewhere the person with the longer crank is still having to do 3% more work, probably in the longer circle that they have to pedal.

[LivingProof]

Jim,

I'm not sure I agree that it's as simple as you have described. If a certain torque (measured in foot pounds) is required, then a longer lever ( the crank ) means that less force is required to push on the lever. But, the actual geometry of a pedeling stroke is so complex due to to all the angles involved. I'm thinking that real life experience over the years has led to the present crank arm lengths, and, it just works well to use longer cranks for those with longer or stronger legs.

For the recreational cyclist, we get to pick the gears we ride and control knee stress by picking easier gears ( or at least I do ). Again, it's not simple especially when climbing, as you may need to overstress knees once max'd out on a long climb. Years ago, the training guidelines stated to stay out of big chainrings for the first 1000 miles of the season and learn to spin.

It may be that a roadie has the advantage in controlling knee stress as, unless we climb, there are few times when the knee is overstressed. I know when I train in the winter on paved trails in a park that has many short climbs, I do beat up my knees more than on a road bike, so I think MTN bikers may have higher risk as flat terrain is not common. Perhaps, brute force  is used in place of subtle technique, but, I've no experience in MTN biking. Then again, maybe I'm just trying to work harder in a shorter riding period and the knees pay the price.

But, as usual, I've been proven wrong......many times in my life.

[jim-ratliff]

Living Proof:

I started out with the intent of just addressing Lynn's comment about longer cranks create torque on the knees.  There really isn't any torque on the knees from a pedaling motion (not like pivot slipping skis, which does torque the knee I think).

Then I got carried away.  The link that BushWacka included makes the point that crank length is more of an arrived at compromise (much of which is ground clearance) rather than an optimal setup, and he recommends much longer cranks in general (and sells same).  Kind of an interesting read.

But in general my assumptions have been the same as yours, that there was a reason that shorter cranks were used on smaller frames and for shorter people and longer cranks on larger frames and for taller people, and that the difference may not be performance driven.

[Svend]

I'm not sure I have anything intelligent to add to this discussion of physics and bio-mechanics in cycling, other than to say that my cranks are longer than I thought.....and my wife says my cranky moods are longer too...   

Seriously, I actually measured the cranks on my 29er, and found them to be about 178, center pedal axle to center spindle.  The shop must have put on longer ones than stock, to make them fit me better.  I am grateful for that, as it seems I've hit the sweet spot in seat position, bar reach and height, and crank length.  Since I made the adjustments last week, the knee pain is all but gone.  Pedaling is MUCH smoother and more powerful, stability is better, and most importantly, the stress on the knees is noticeably diminished. I think I will move my shoe cleats back to bring my feet more inward again, but that is all I will do for now.  May play around with bar position at some point, but just want to enjoy the riding for a while and not make too many changes at once.

I went on my first single track ride tonight, and the bike just felt great.  So stable and smooth, steering was spot on -- agile, yet not squirrely -- and hill climbing was great with the new alignment.  It's all good. 

 LP and JR:  as for your discussion of crank length, it seems you are both coming to the same point from a different direction -- it is true that a longer crank creates more turning force (torque) than a shorter one for a given force on the pedal; and conversely, it is also true that a longer crank requires less force on the pedal to create the same amount of torque as a shorter crank.  For a taller rider, having a good geometric fit that a longer crank provides seems (logically) to have the added benefit of making pedaling easier.  OTOH, does that mean a shorter rider has to work that much harder? Not sure about that one, as, like Jim said, smaller riders weigh less (usually), and the geometry of the bike frame is totally different for the smaller size.  Seat tube angles, wheelbase, etc., are different for smaller frames, but I really have no idea what effect that has on pedaling efficiency.

Interesting discussion, and having made some minor tweaks to the alignment of my bike, I am amazed at how much benefit (or loss) can be had from just a few centimeters adjustment.  Kinda like skis and boots too......same analogy.  A small change can translate into big gains. 

[bushwacka]

i have extremely strong legs, but even last year when I played around with 180cm VS 175 and 172.5 cranks on my road bike with an SRM the 180s had one downside. My 5 second power(IE sprinting)  dropped by 223 watts from 175 to 180, IE the 180 was less power, My 1 minute, 5 minutes and functional threshold all went up with the 180s. the 172.5 were not better in any time range in fact they for me the jump from 180 to 175 was less than 175 to 172.5.

I have no idea how to make a graph for this from my SRM files but here is what I have all number in watts, realize that outside of the 5 second time these numbers are nothing special for a 175lb cyclist.

180
5 second  - 1621
1 minute - 767
5 minute - 409
FT - 313

175
5 seconds  - 1844
1 minutes - 721
5 minutes - 393
FT - 298

172.5
5 seconds - 1656
1 minutes - 656
5 minutes - 310(biggest drop off)
FT - 274

the deal is no matter what I did on any of my bikes my knees just simply would not agree with 180s. Not to mention the clearance problems when MTBing, Cross riding or Crit racing. In crit racing your 5 second power and sprint is the most important thing.  I really need to get a pair of 177.5 to try out and see if I can make them work. BYW Sven your cranks are 177.5 they dont make 178 and I bet it says it on your cranks somewhere what size they are.  I also want to add that my average cadence when road riding is 97 rpms depending on the day. I can grind with the best of them but can spin with the best of the as well. Its what riding a SS bike will do for your pedaling.

I do find it funny that hard core roadies insist on running 172.5 so that can spin faster and smoother, which doesnt mean more power.

[jim-ratliff]

Bushwacka:


Thanks for posting the numbers, that's very interesting even if mostly over my head.  Some curiosity questions.


Did you need to adjust alignment (i.e. seat position) with the various cranks?


Did you feel as if you had worked harder when pedaling the 180 crank?  Or did it feel like a similar level of effort resulting in higher watts? (except for the 5 second number)


Were you able to maintain cadence with the larger crank, or was cadence a little bit slower since your feet had to make a bigger circle?

[bushwacka]

Once I had my position as comfortable as could be on the 180s I just used it for everything.

For me the 180s actually felt easier to produce power on, my cadence dropped slightly in fact so slight that its not worth mentioning. My leg were underworked but my heart was screaming on the 172.5..

[jim-ratliff]

My legs were underworked but my heart was screaming on the 172.5..

I find that a really interesting assessment from a pretty fit biker, especially given the old mantra about "don't push the gears, spin them". 


And I'm very surprised that there's that much difference for such a small difference in length.  1 inch = 2.54 cm = 25.4 mm.  So 2.5mm increase in crank length is only 1/10th of an inch.

[bushwacka]

Jim keep in mind that I am no means a grinder either. On my road bike I average 95 rpms which is pretty normal compared to other Cat 2 roadies, Cat 1 cross riders.

[meput]

Crank arm length has always been a controversial topic. When I rode in grad school in the mid '70's, 165mm - 170mm were the norm. Now the norm is 170-175 for men's road bikes OEM. Shimano Dura-ace cranks (Hollowtech) are currently available 165mm - 180mm in 2.5mm increments. General rule of thumb is the taller the rider, the longer the crank arm length. You are looking at spending big bucks to change crank arm length in the aftermarket. As a result, most riders accept the length that comes with their bike. The question as to length comes up most commonly when a rider is doing a custom bike (either with a custom builder or building a bike up from a frame), or when a rider has a problem (like knee pain or back pain), or when a rider just wants to experiment (usually a racer with access to enough other bikes/crank arms of different lengths with mechanical expertise to do the swapping).

Of interest, a lot of the riders that I know are trending to go shorter (if they have a choice: replacing a crankset or getting a new bike) as they age (50's +). Easier to spin and less stress on the knees.

Lennard Zinn recently wrote on the topic in his column on the VeloNews site: http://velonews.competitor.com/2011/06/bikes-and-tech/technical-faq/technical-faq-with-lennard-zinn-when-it-come-to-crankarm-length-no-easy-answers_178528

FWIW, I am 5'4" and spin a 165mm crank.

[jim-ratliff]

Jim keep in mind that I am no means a grinder either. On my road bike I average 95 rpms which is pretty normal compared to other Cat 2 roadies, Cat 1 cross riders.

I should have explained.  My amazement was that the spinning on the short crank was an aerobic (heart) challenge without really taxing the leg muscles.