Bike Fit Question - Leg Length Discrepancy

[melissam]

I read about the American Classic seatpost, which allows the head to be tipped slightly to either side to help correct leg-length inequalities without shimming shoe cleats. Since I have a ~1 inch leg length discrepancy that I've addressed in the past by shimming cleats, this approach is very interesting to me.

But then I got to thinking -- is it a good idea to address this issue by tilting your saddle laterally towards your short leg's side? While this may address the leg length discrepancy, wouldn't it cause issues in your low back? Or your neck & shoulders if you're riding off to the side?

Has anyone tried this approach?

Also, does anyone know how far you can tip the seatpost? 2mm? 5mm?

Finally, does anyone know if there's an issue with using an aluminum seatpost in a carbon frame?

Thanks in advance for any insight you can offer.

-- Melissa

[KnottedYet]

But then I got to thinking -- is it a good idea to address this issue by tilting your saddle laterally towards your short leg's side? While this may address the leg length discrepancy, wouldn't it cause issues in your low back? Or your neck & shoulders if you're riding off to the side?

I wouldn't suggest it to any of my patients. We spend beaucoup insurance $$ correcting the effects of LLD on someone's pelvis and low back.

I'm pretty amazed by this critter. I might have to write a *special* letter to these folks.

[melissam]

Thanks, Knot.

If you want a link to the product in question, here it is:
http://www.amclassic.com/seatposts.html

Maybe it's an OK solution if you only correct slight LLDs with this method? Like a mm or two? I dunno.

At first glance, I really liked the idea of correcting the LLD without having to shim my cleat, especially since I've switched to recessed cleats on my road bike. Without any correct, my low back can get heck-a-sore after a couple of hours in the saddle. And now that my training rides are getting into the 3-5 hour range, well, let's just say that my legs aren't necessarily the sorest part of my body after a ride.

Oh well, my next approach will be to use full foot orthotics in my cycling shoes. In effect I'm going to put the shim inside my cycling shoe and enjoy the convenience of recessed cleats and have a happy back to boot! At least that's my theory...

-- Melissa

[KnottedYet]

Specialized makes some very nice non-compressible forefoot lifts/shims that go inside the shoe. Unless you already have orthotics that you want made into full-foot, I'd be looking at the Specialized goodies.

(If you already have orthotics, your Orthotist will know the lift at your heel and should have no problem just *giving* you a slab of cork the same thickness for your forefoot in the bike shoe.)

[melissam]

Thanks again, Knot!

I have a pair of orthotics on order from the Orthotic Group. Their rep was in the office and we did a scan of my feet/gait while walking -- fascinating stuff! Turns out that my bad leg has a pretty normal pattern but my good leg does some pretty funky gymnastics to compensate for the bad leg.

Anyway, the orthotics should be here by the end of the month, and I'll give 'em a go. If that doesn't help enough, I can always compensate by tilting my saddle to the side with that seatpost. (Just kidding.)

-- Melissa

[Triskeliongirl]

A 1" LLD is huge, and unlikely to be fixable by cleat shimming or orthotics. I only got resolution with a custom crank set with a dropped pedal (mine is 3 cm) from Tom Slocum at High Sierra Cycles. I highly recommend his approach. All other approaches gave me terrible hip and back pain, that tooks months for a PT to fix.

[KnottedYet]

Oh, yeah! I'd much rather see an effective crank length/dropped pedal adjustment than a side-tilting saddle.

A lot of times what we start with is correcting 1/2 the LLD. So for a 1 inch LLD we put in a 1/2 inch lift or lift-and-shim combo (cuz your bod has been compensating for that 1 inch your whole life and we don't want to push it all the way to the other side and cause a new problem!)

If your orthotics and cleat shims don't make the world a better place, I'd suggest seeing either Michael Sylvester, Chris Robinson, or someone they recommend. Someone like me, with more PT training than bike-stuff training, might not know about the nifty stuff you can do at the crank/pedal.

(interesting aside: did you know that Bill Nye the Science Guy designed a bike pedal lift for LLD?)

Edit: has anyone talked to you about putting lifts in the outsole of your shoes, as opposed to inside the shoe? This kind of trick works peachy-keen with regular shoes, is a lot cheaper, and you never have that "OMG, my orthotics are in my other shoes!" moment. You usually want to have experimented with lift sizes before you go make structural changes to the shoes.

[Mr. SR500]

John Howard briefly touches on LLD at the 6 minute mark of this You Tube video. Good Stuff.

http://www.youtube.com/watch?v=DWOn3...eature=related

[melissam]

Thanks for all the great input!

Trisk,
If the whole shimming/orthotic thing doesn't work, I'll consider the custom crankset. My hip & back were reasonably happy with the shimmed Look cleat, so I may be able to get away with having half of my LLD corrected. I hope.

Knot,
I have corrected the outsoles of some of my shoes. I probably own one of the few pairs of Platform Tevas -- think '70's. OK, only the left one is a platform Teva, the right one is standard. I also have a platform Birkenstock. Yep, I'm just way too cool.

Mr. SR500,
The John Howard bike fit videos were interesting -- thanks for pointing me to the spot where he talked about LLDs. I may be wrong, but it seems that his point was that the LLD may be due to anatomical issues or muscular issues. He went on to say that 9 times out of 10, the LLD vanished after he made adjustments to patients on the table. He also said that correcting with shims exacerbated the problem as it extended it rather than levelling it.

Seeing the video has raised some additional questions:
1. What if the LLD is due to an anatomic issue that can't be corrected with adjustment? In my case, I had a spiral fracture of my left femur; each fracture point lost about 1/16" during healing, and if you do the math, well, my left leg is about an inch shorter than my right. Can this be corrected with adjustments? Or is this the type of problem that is best corrected with shims?

2. If you make soft tissue adjustments to correct LLD issues, is it a one-time deal, or does the area have to be adjusted periodically? Who's qualified to make these types of adjustments? PT? Chiropractor?

I'm not sure if I'm wording this well -- I'm not really expecting anyone to give me the answers, I'm just expressing my curiosity and am interested in hearing others' opinions or thoughts.

Thanks again to all who've weighed in on this.

-- Melissa

[KnottedYet]

If your LLD is structural (like from a fracture) soft tissue adjustments ain't gonna cut it. You're doing the right thing by shimming/lifting your shoes.

[aicabsolut]

It can help to tilt. It can also help to beef up one side of the saddle with extra padding. You may also just be able to split the difference and not feel too bad.

There's a real expert on this fit issue at cyclingnews.com on the fitness q&a page (Steve Hogg). There are gobs and gobs of questions and responses geared towards functional and measurable leg length discrepancies of various amounts with various ways to tackle the problem. You can get a lot of good information there.

[Mr. SR500]

I think John covers the basics on the videos, but we were with a week, so there were lots of details, bottom line is I think it's very difficult to say without a very good bike fitter helping you.

I've gone crazy with fitting, I've been professionally fit, John Howard gave me several good pointers and I've experimented myself. My legs vary some as I believe many peoples do. My chamois also use to slide to the side about 1/2". So I tried Lemond shims (I still use 1 for each shoe), but I've tried tup to about 6 on one leg. The shims I use now are for tilt. I've adjusted my cleats, fore and aft of each other, sliding the cleat of the longer femur forward, and the other back a bit. I've even enlarged my seatpost saddle binder so I could shift my saddle off center a hair.

Nothing seamed to really make a difference, so I've basically gone back to neutral and stopped trying to figure it out. I never did have pain, but just wanted the best fit. So other the one LeMond shim under each cleat, my bike setup is "normal". A I've not had problems with mileage or pain (longest ride is the RAIN ride in around 9 hours for 160 miles).

So I would go with what makes you comfortable, but if needed find a good fitter and work with them.

If I lived near San Diego, I would go to John, and I'm sure he would dial me in on the bike, give me a stretching routine especially developed for me, and make some corrections. But I live in Indiana, my fit is close, and I don't have any comfort issues, so I just focus more on getting faster and riding.

Best of Luck - it's a very interesting subject...

[Triskeliongirl]

I will say it one last time. Shims cannot be used to effectively correct a 1 inch LLD. Shims are great for correcting smaller LLDs, on the order of millimeters, as are some of the other techniques mentioned. The reason is that with a large shim, while your leg can be the correct distance from the pedal (and knee angle) at say the bottom of the pedal stroke, at the top of the pedal stroke, its like having a crank that is an inch too long and will raise your knee too high and cause a sheer force on your knee. I too worked with local fitters, got shims, got the idea to try different length crank arms, and contacted Lennard Zinn to obtain some. He immediately referred me to Tom Slocum of High Sierra Cycling. His dropped pedal system is ingenious, because it continuously adjusts throughout the pedal stroke so you are always the perfect distance from the crank arm. http://www.hscycle.com/Pages/cantsandwedges.html
He then offsets the chain rings to balance the leverage throughout the pedal stroke. He is an engineer that specializes in this, and has done work for several elite cyclists (olympian alexi grewel for example). I highly recommend him.

FYI, my 3 cm LLD was caused by a cycling accident. Like you I lost bone. In my case one sit bone is shorter than the other, and one of my hips is twisted relative to the other after my pelvic, hip and back fractures healed. The end result when I sit on a bicycle seat is that one leg hangs down 3 cm longer than the other. But, with Tom's system I feel biomechanically normal on the bike, better than I do walking even with shoes that are fit with lifts, etc. (which is also imporant though!). I'll never run again but I can cycle like a normal person. I also think my brooks saddle helps, since it accomodates the asymetry in my sit bones well (marks are deeper on one side than other).

[KnottedYet]

I was talking about her regular shoes. (the platform Tevas and Birkenstocks, etc.)

I completely agree with you about the crank adjustment. Those are groovy!

[Triskeliongirl]

Absolutely Knotted! I wear a lift in my shoes that is essential to walk comfortably. Its funny the shoe lift isn't as large as my bike correction, but I think that is cuz my LLD is different standing than when on the bike, due to the specific nature of my fractures. Also, it may be that my body had partially adjusted before I started wearing lifts, so correcting the full amount was too much. I buy these very inexpensive lifts: Actually, I started with these cuz they are adjustable
http://clearlyadjustable.com/
but once I realized I needed the full correction prefer these: http://gwheellift.com/plastic-heel-lifts.html
I use the 12 mm in the shoe of my short leg side, sticking them in with the tape you can order from the same company. Not all shoes can accomodate such a large lift, but I find they are great under the insole of a Nike Air Pegasus running shoe. I bring them with me when shoe shopping to be sure the shoe is deep enough. I find if I try a larger lift, I run into other problems, like either the shoe can't hold it, or I start to feel unbalanced, like one foot is walking on high heels and one on flats, perhaps another reason I settle for an incomplete correction.

Actually, if you are interested my on the bike correction is 2.2 cm. While the first bike fitter measured me at 3 cm (distance from top of femur to ground while standing), Tom's on the bike measurements came out to 2.2 cm (he raises plates under your feet that meet your feet while you are seated on your bike to get the on the bike measurement).