Cycle orthotics

Fred:

Your explanation only makes "half sense". Please explain the biomechanics of how using a shorter crank arm on the short limb in cyclists is "the better option" when at top dead center the shorter crank arm doubles the effective LLD and using asymmetrical crank arm length will produce asymmetrical demands on power output from the two limbs due to the decrease in crank arm length on only the short limb side.

http://sheldonbrown.com/cranks.html

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

http://www.livestrong.com/article/355966-how-to-cycle-with-a-leg-length-discrepancy/

Also, Fred, check out pages 77-78 in this book, High Tech Cycling, by Ed Burke and Andy Pruitt. No mention of using a shorter crank arm for limb length discrepancy by these experts. I guess these guys are only "half right" also?

http://books.google.com/books?hl=en..._JpDAy1GYbVxqkN-DqtuWWayc#v=onepage&q&f=false

 

Hi Kevin, Mike and all,

I should not have said "rocking" on the saddle as I agree with your point above Kevin about the primary cause of this.

I should have said a slight shift in Pelvic orientation on the short femur side.

If we look at the simulation study on crank power below and the attached figure from the study I will attempt to explain myself a bit better.

On the attached figure if the femur length was shorter on one side it may change the "desired " pelvic orientation when commencing the pedal stroke from top Dead centre. There will be a point where the force vector is more horizontal just before the downstroke proper is initiated.

A shim corrected short tibia will still hang directly under the knee as the foot/pedal comes down to a horizontal position whereas a shim correction for a short femur will not due to equal crank lengths .

I wonder if there is a change in pelvic orientation on the short femur side that may cause an anterior shift on the saddle in an attempt to have the knee drive straight down over the pedal axle.

Anecdotally I see more people with saddle rubbing issues on this short side (even after shim correction for a short femur) and that is my guess for why it is happening. It is just that though.....a guess.

As I said previously, I think in most cases a shim to correct a short femur will work fine. There is some nice research to be done here on power output though I think.

Regards,
Athol


Journal of Applied Biomechanics, 2010, 26, 493-500
© 2010 Human Kinetics, Inc.
Jeffery W. Rankin and Richard R. Neptune (Corresponding
Author) are with the Department of Mechanical Engineering,
University of Texas at Austin, Austin, TX.

Crank Power During Pedaling: A Simulation Study The Influence of Seat Configuration on Maximal Average

Conclusion
The simulation results showed there exists an optimal seat height, Seat tube angle (STA) and pelvic orientation (PO) that maximizes crank power. However, maximum power is most sensitive to seat height. Similar power output levels were observed across all STAs, which were achieved by systematically shifting the pedal angle with increases in STA to allow the hip, knee, and ankle joint kinematics to remain within the optimal range for muscle power generation based on the force-length-velocity relationships. Thus, there does not appear to be an advantage of one STA vs. another when maximizing crank power. However, adjusting the STA will affect riding posture and aerodynamic drag, which has been shown to greatly influence cycling performance. Therefore, modifying the STA may allow a rider to achieve a more optimal upper body posture that minimizes aerodynamic drag without greatly sacrificing the ability to generate maximal crank power, which will ultimately improve overall cycling performance.






Figure 1 — Right leg of the bicycle–rider musculoskeletal
model. The model has nine segments (2 legs, pelvis, crank
and pedals) and 10 muscle groups defined as SAR (sartorius),
PSOAS (iliacus, psoas), RF (rectus femoris), VAS (three
component vastus), TA (tibialis anterior), SOL (soleus), GAS
(gastrocnemius), BFsh (biceps femoris short head), HAMS
(medial hamstrings, biceps femoris long head), and GMAX
(gluteus maximus, adductor magnus). Seat configuration was
defined by three parameters: seat height (H), seat tube angle
(STA), and pelvic orientation (PO).

 

Hello again

I think maybe the confusion is by thinking of, and treating LLD the same way as we do with running and walking.

On the bike, everything is different.

Generally shorter riders use shorter crank arms, taller etc. Crank arms vary between about 170cm to 190cm although if varies with manufacturer. It's really dependent on whether the rider wants torque or rpm. It's usually thought that a longer legged rider can produce more torque, but I don't think that's it.

The longer leg produces more motion for a given angle of the hip, knee. The lever arm is longer, so the motion is greater. This is I think why taller riders are more comfortable with longer crank arms.

The lower extremity makes maximum power when the hip and knee are relatively straight compared to fully flexed. This is why the crank arms are relatively short. We don't have long crank arms that flex the knee over 90 degress for example.

The first reason we adjust a rider for LLD is to prevent hip roll on the seat. For the long leg to straighten enough, the short leg has to straighten too much, and the hip will drop on that side. A shim works for this.

But really, when you have a rider with a short leg and a long leg, you have two riders, a short one and a long one. To maximize comfort and power the long leg needs a longer crank, and the short leg needs a shorter one. At bottom dead centre, both legs will be accommodated and knee flexion angle will be the same, which is what's most important. Hip roll is accommodated. At top dead centre, the long leg knee will be higher than the short leg knee, but the knee flexion angle will be the same, again the most important thing. All this needs to be explained to the rider so that he understands the rationale, because a rider being seen for bike fitting is by definition a bit OCD.

Obviously the rpm is the same from one side to the other. The muscles are working at their most productive/physiological length, which evens out the work from one side to the other.

Actually, power production from one side to the other is determined primarily by the rider, and how hard he pushes. If one side feels weak, or sore, the rider will tend to push a little less hard, the good side taking up the slack.

I hope this makes it clear, but rather than someone saying it's wrong because no one else does it, I think it might better if someone could write as to why this line of thinking is wrong.

Cheers

Frederick

 

Which thru the training effect will lead to greater strength on 1 side and an imbalance of strength from left to right legs - which is what we should be trying to avoid as this often leads to overuse injuries in the engine room of the cyclist - the lower back and gluteals.

So if we can through the use of Physics determine which leads to a better muscle recruitment profiles, power production and less Pelvic orientation issues must be the better way.

by splitting the cyclist with a LLD into 2 separate cyclists for bike fitting it would concern me as to the long term effects.


as I now see would be a problem with a longer crank arm on the short side, definitively with muscle recruitment and power production.

PS Athol I have not read the study but will today does it discuss when during the power stroke the most power is produced - I guess this would be different person to person, but say we have a person who produces the most power a 2 O´clock and another at 5 O´clock then if you were going to adjust the crank arm or Shim it might not be a positive to even the LLD and thus knee and hip flexion at about this point ?

 

Hi Mike,

The simulation study does not go into power production at different points in the pedal cycle.

Usually, the most power is produced at about 3 o'clock when gluteal and quadriceps contraction overlap and the leg is perpendicular to the crank. See diagram. (not sure of the original source of this so it may not be perfect but illustrates the point)

As you say, everyone is different though and 'ankling' or riding with excessive plantar flexion at the bottom of the stroke will alter things a bit.

I'll dig out the papers that do go into this and get back to you.

Sorry Mike I'm not sure I understand the question about the LLD?

Regards,
Athol

 

Dear Mike

This really doesn't approach what I was saying. What I was saying is that the human rider has much more control over the power he produces than we, as doctors, do. When he tires, he will push less. If he cramps, he will push harder with the other side.

Your quote is all supposition, and not based on the physiology of what I was saying. What I was explaining is how to accommodate for the imperfection (LLD) of the rider.

Also, the longer crank arm is on the long side.

And Mike, both cranks are at the same rpm.

Cheers

Frederick

 

Story of my last few days posting.

If at 3 o'clock the cyclist is produces the most power would this not be the point we would want the extra shim to equalize the LLD so that the hip,knee and ankle are at similar angles on both sides. Thus increasing the chance of equal power production ?

Kevin said that he increase seat hit half the distance of the shim, this got me thinking. Probably not right but .....

 

I can't get my head around the idea of a short crank arm for a short leg but am thinking that in my experience addressing the cleat/shoe interface or inside the shoe when possible makes much more sense.

As for power output regardless of how tall or short the rider is and which allegedly produces more torque and which more rpm, crank arm length is more a decision of overall fit on the bike due to physical characteristics relative to height. Torque and rpm are ultimately decided by the crank to cog ratio the rider's output and strength are they not?

 

I am a keen follower of the Podiatry Arena blog and feel it is a great forum for exchanging views, experiences and expertise.

I was somewhat alarmed recently however by the following statement from Dr Kirby regarding Solestar.

His quote........
BTW, I seriously doubt any prefab orthosis has the ability to increase "performance" by 6.9% in a large range of cyclists. This smells of marketing BS, similar to the butt-toning claims of the "toning shoes" that are now being forced to refund money to their customers for their unsupportable marketing claims. Please tell the company that I made this statement publicly and that they will need to produce some good scientific research evidence in regard to their claims or be prepared to start refunding money to their customers if their 6.9% improvement in cycling performance claim doesn't hold true for the customers who purchase their pre-fab cycling orthoses.
I feel these comment are not in spirit of the blog, they not respectful or thoughtful.

As the Australian representatives of Solestar, I feel duty bound to respond to Dr Kirby's statement.

Firstly, making this statement when there appears to be have been no attempt to review the paper published and presented by the Koln Sports University at ECSS congress 2011 before dismissing this as “marketing bs”, is somewhat premature.
This institute is not without recognition. It was the institute the IAAF asked to assess whether Oscar Psitorius, the South African sprinter and double amputee gains any unfair advantage from the use of his artificial limbs and whether he would be eligible to compete in International Athletics events with able bodied athletes such as the World Championships and the Olympics..

Secondly, making this statement prior to seeing the product or having spoken to any one who has used or been fitted with the Solestar before dismissing it as the cycling equivalent of the “butt toning shoe” is ill informed.

I would expect someone of Dr Kirby's credentials to be a little more inquisitive of a product like Solestar and far less dismissive.

To provide some background to Solestar we asked its German developer Oliver Elsenbach to provide some comments for this blog.

Oliver Elsenbach, a German Sports scientist who has spent many years now working with elite cyclists and sportsmen. I have posted Oliver’s comment regarding the development of Solestar below in response to this thread on Podiatry Arena.


Dear Podiatry Arena

Since there has been a long discussion on the ways that cycling orthotics work and our product Solestar was mentioned here I would like to give a bit of background information on this subject.
I have studied sports sciences in Cologne. After my studies I began work with orthotic insoles at a german orthopedic shoe meister for a few years. Being a cyclist myself I started to do individual insole fitting focusing on athletes, majorly cyclists. It started out as optimizing the athletes primarily for their problems and pains in riding. Most of my athletes work with SRM powermeter and once after I did a fitting in 2005 an amazed rider told me that he had gotten an increase of 120 Watt of power output when he sprinted with the insoles in the race. This showed me that the individual insoles not only were reducing problems but also potentially increasing the performance. I started to develop on the concept of the Solestar insole.
We have tried more than 200 different prototypes for the Solestar insole. Every component of the insole was tested. Various materials were tried out. In the end we went for a special carbon material, which was produced just for the insole. The carbon simply offers a perfect combination of stiffness and flexibility while it's extremely light and thin. Also it could store energy while pushing and give it back while pulling.
Since 2003 I have fitted about 5000 insoles for cyclists all around the world, the last 3 years concentrating on cycling and the best cycling insoles. I have worked together with the Danish track national team, with Team T-Mobile, Team Columbia and Team Milram.
The most important thing for me is that the rider is happy with the insoles. He has to feel a better contact to the shoe and pedal and the cycling feels more controlled. The last two years I have always done a test on the ergometer (with the athletes own bike) without and after fitting with our carbon insole. 150W, 300W, 400W, always with a positive feedback. We measure the foot pressure, have SRM torque analysis and do different kind of testing (isokenetic 8 sec, 30sec and 4min). My customers have very seldom any orthopedic problems, they come to get a better performance.
A lot of pro-tour riders use the Solestar insole. For example Andy and Frank Schleck, Fabian Cancellara, Andre Greipel, Johan Vansummeren and many more. We are a young and small company still and we never paid any money to the athletes who are using our insoles. Actually most of them had to pay for the insoles.
The information on the increase of of 6.9 % in sprint performance by using Solestar cycling insoles is the result of a scientific study done by the Cologne Sport University (DSHS). We were actually hesitant on using this result in our communication because it would appear like the typical marketing blabla you see in ads and provoke the reactions we have now seen here. But the DSHS (www.dshs-koeln.de) is one of the most reputable institutions regarding sports sciences in the world and the result shows that insoles are not only for those cyclists with problems, so we decided to publish the findings. On top of that, the study was also published by the ECSS at their congress in July this year. It's an important scientific sport congress for Europe: http://www.ecss-congress.eu/2011/
We also work together with the Russian track national team and on the track you can measure time. The Russians (25 athletes) came to our place in Cologne just this autumn and all got individual insoles in their Bont cycling shoes. Maybe it is not only due to the insoles, but the Russians won the 4.000m hunting in the final with 03:56 min against the Australians (04:01min) at the UCI Track World Cup in Astana just a few days ago.
Bottom line is that a good orthotic insole can almost always get the rider trouble free while increasing his performance significantly. 90% of the riders we equip with the insoles today are already trouble-free when they come to us and only look for added power.

Oliver Elsenbach

If anyone would like some further information on Oliver and Solestar please contact me and I would be happy to oblige.

Regards

Quinton.
Solestar Australia
quinton@solestar.com.au

 

Quinton:

Sorry if I offended. I was just speaking my opinion from my years of reading the research literature on cycling biomechanics and from my 27 years of experience in treating cyclists with custom and prefab foot orthoses. So, Quinton, since you work for Solestar and Oliver helped develop the Solestar (I assume he has a financial interest in the product also), then I should assume that there was absolutely no marketing bias in this study and in your responses to my comments?

I will be more than happy to be much more enthusiastic and more likely to believe the Solestar insole claims of a 6.9% improvement in cycling performance if 1) the research is performed in a manner that is well-controlled and 2) its results also point to similar improvements in cycling performance with the Solestar insole.

I will anxiously await the results from this independent, well-controlled study and, if you notify me of the results of this study, I will be the first to say that I was wrong regarding my first impressions of findings of 6.9% improvement in cycling performance with the Solestar insole. I really don't mind being proved wrong...but think that the likelihood of me being proved wrong in this case is minimal.

Good luck with the marketing of Solestar insoles.

 

Kevin,

The abstract of the study is here:

http://www.solestar.com/assets/files/material/studien/Abstract_SOLESTAR_EN.pdf

My bad, already posted

 

Dear David

I agree that the shim idea makes more sense at first, because it is simpler. It is simply what we do with runners. But with a bike, the foot transmits force on a moving medium, unlike the ground which is always in the same place.

There is an optimum range in flexion and extension where the lower extremity makes the most power. We reach this primarily by how it feels to the rider, which is a pretty accurate way, given that there is no other way, anyway. We adjust seat height, and we adjust crank length for this power, endurance, comfort. This range relates to optimum proportional muscle length, which of course relates the the flexion and extension angle of the knee, hip, ankle.

In order to have the same optimum proportional muscle length for each side (short/long) we must have the same flexion and extension angles of the joints. The longer limb has a greater change in total length than the shorter limb with the same flexion and extension angles of the knee, hip, ankle.

So therefore, to keep proportional muscle length in this optimal range (same flexion/extension angles) the long limb has to move further, and needs a longer crank. The short limb doesn't move as much with the same flexion/extension angles, and needs a shorter crank.

With a shim, one is effectively moving the whole crank set higher on the short side. This does correct for hip wobble, but the joints on the short leg must go through greater flexion/extension angles than the long leg. On one side or the other, these angles (and the associated proportional muscle lengths) will not be optimal. So one leg will be making power more efficiently than the other.

Some riders have never experimented with different crank lengths, and don't know what is best for them. This must be sorted first. Then the fine tuning can be done to adjust for the difference in limb length. Usually it feels better for the rider to go down to a shorter crank length on the short side after he is generally happy with the crank length. A longer crank provides more torque, but is harder to spin.

I know this is a detail, but little details are what bike design, fitting, and racing are all about now.

Hope this helps.

Cheers

Frederick

 

So, the short crank makes everything fine at bottom dead center. At top dead center the short crank will create a loss of flexion of the leg that will be double the limb length difference. Wouldn't that move the pedal position farther from optimal seat height than a shim.

With the shim, the change in flexion extension angles would be less than the change with a short crank. (The change is in opposite direction and a different point in the pedal cycle, but still a change.)

Eric

 

Frederick.

Thank you for your detailed response. Eric posed the same questions that I am thinking and much more succinctly than I ever could. My problem with the short crank idea is that you will end up with a very different torque and rpm (watts) value from one side to the other, precisely the situation that you are trying to correct with a significantly short leg. I don't see how that results in an appropriate solution to the original problem?

Eric I remember reading somewhere that compensating for a short tibial length is best accomplished with shims/shoe buildup and a short femoral length is best accomplished via a shorter crank on the affected side. I'd be very curious to read your thoughts on that if you have any?

Regards,

 

Just thinking about it. The femoral length will matter most when the crank is horizontal on the downstroke. Here the distance, in the sagittal plane from the pelvis on the seat, will change the resistance leverage of the pedal on the hip joint. In other words, a short femur will need a short crank to put the pedal more under or more rearward relative to the knee. I think this is why taller riders will like longer cranks or shorter riders will dislike longer cranks. That said, the difference in femoral length from a tall rider to a shorter rider will be a whole lot more than the difference from one leg to another. Say you had two riders that had an inch difference in femoral length. Could they both choose the same crank length and be perfectly happy. From what I've read, the biggest problem from limb length is hip rocking. This effect occurs at bottom dead center both when the femur is long and when the tibia is long. So, the rationale for using shims, in the previous post still applies. That's me just sitting in my chair and thinking about it.

How many discreet crank lengths are on the market?

Eric

 

When I work on cyclists, the limb length discrepancy seems to manifest itself as frontal plane rocking of the pelvis which is eliminated with cleat shims, regardless of whether the shortness is in the femur or tibia. However, with a shorter crank on the shorter limb, instead of a cleat shim, the knee angles would probably be kept more constant between the two limbs which may improve mechanical efficiency, but this would occur at the expense of more pelvic rocking since now the limb length discrepancy would be accentuated by putting a short crank on the short limb side.

Would be interesting to see if any research has been done on these factors since I can definitely see the benefits of both approaches. Anyone know of any research in this regard?

 

I spent some time on Google and couldn't find anything Kevin. Simon & Mike are really good at locating studies, maybe they'll give it a look? Sounds like a great research project, if I actually knew how to do research...

 

Here is a nice little discussion of why not to use crank arm length adjustments to treat leg length discrepancy in cyclists that just so happens to agree with my observations in treating cyclists.

http://www.sheldonbrown.com/cranks.html

 

Hello again.

Well, I wasn't impressed by Sheldon "Cranky" Brown's opinion!

13 Nov - Kirby

5 Nov - Kirby

Kevin, now you have the two benefits of the shorter crank. "Improved mechanical efficiency" and "equalizing out the limb lengths."

This "problem" of the limb length discrepancy being worse at top dead centre doesn't matter at all. The leg is just riding along at top dead centre. This doesn't cause hip wobble, that only occurs when stretching at bottom dead centre.

Anything that can improve mechanical efficiency on a bike is gold.

Cheers

Frederick

 

Fred:

The problem is that we don't really know which method is more "gold", as you say, adding a cleat shim or altering the crank arm length. We are all only speculating since there seems to be no research in this regard.

However, what is obvious in reading numerous articles on this topic over the past few weeks, it seems that most bike fitters prefer cleat shims rather than altering the crank arm length for treating limb length discrepancy in cyclists.

As for putting a shorter crank arm on the shorter limb which effectively worsens the limb length discrepancy at top dead center on the short limb, my bet is that this is not the most mechanically efficient method for treating limb length discrepancy in cyclists.

Do you have any evidence otherwise?

 

Trying to achieve some other things at the moment - so not posting thoughts and idea but will look for articles during patient breaks today as this thread has been a great thread - re cycling

Fredrick - clearly both are travelling at the same rpm but re my RPM idea with different crank arm length we might have 3 different things which could occur.

1 side travels with perfect RPM for power output the other

1 - travels too fast for maximum power output and thus is not maximally efficient during the power stroke

or 2 Travels too slow and thus may fatigue quicker due to the fact that the power stroke takes longer for one side than is the perfect balance between RPM and power output

or It does not matter.

anyways papers which people may find of interst.

Nothing on LLD and crank arm v´s shim re power production or biomechanical changes by using 1 v´s the other

A theoretical analysis of preferred pedaling rate selection in endurance cycling

Determinants of metabolic cost during submaximal cycling

The influence of cadence and power output on biomechancis of force application during steady rate cycling in competitive and recreational cyclists

A new pedaling design: the Rotor—effects on cycling performance

Effect of Crank Length on Joint-Specific Power during Maximal Cycling

Bike fit article

Uncompromising position: here’s how to achieve optimal bike fit

 

Determinants of maximal cycling power: crank length, pedaling rate and pedal speed

Road Bicycle Fit

 

Different to Athols paper

Differences in power output during cycling at different seat tube angles



Influence of Hip Orientation on Wingate Power
Output and Cycling Technique

Lower extremity muscle activities during cycling are influenced by load and frequency

Bilateral pedaling asymmetry during a simulated 40-km cycling time-trial

- Paper looks a dominant leg and crank peak torque and it always being responsible for producing more torque

Effects on the crank torque profile when changing pedalling cadence in level ground and uphill road cycling

 

As Far as I am aware there is no research to show which method is superior as yet.

I have been talking to a friend who runs the biomechanics lab at the local university (which has been recently updated) about use of the 3D motion analysis system and their Watt-bike. The pedals and cranks can be changed on the watt bike so it should be possible to compare the two methods but nothing has been agreed upon yet.

Mike, Thanks for taking the time to post all those studies. Much appreciated.

Regards,
Athol

 

Dear Kevin

You alone grasped the importance of the peak contractile force and the force-length relationship.

I guess you place your bet on gut feeling.

However, as to what "most bike fitters prefer," truth is not determined democratically. On this, we both agree.

As you said on 5 Nov (probably best if you include the quote next time you respond, so everyone else can follow):

You could try the different crank length on a couple of racers, and see what they think. You might be surprised.

Cheers

Frederick

 

Fred:

I can really see it being possible that both methods could work quite well for certain cyclists. Maybe Athol can get some research going and find out more about how each of the methods (shims vs crank arm changes) changes performance, fit and metabolic efficiency. Sounds like a great reserch project!

Thanks for the very interesting discussion!:drinks

 

Athol:

It should be fairly easy to go to the local bike club and find riders who have a known leg length discrepancy and study those individuals initially to know how best to set up the study if you think research is feasible. This would be an excellent research paper and one that could easily be published in the American Journal of Sports Medicine.

Let me know if you need any help with setting up the preliminary study or research project. This is interesting stuff!:drinks

kevinakirby@comcast.net

 

Kevin, Frederick and all,

I would very much like to follow this up with some research. I will set up a basic trial study on consultation with the biomechanics lab boys and my current high performance cycling/triathlon talent squad patients with a known LLD.

If it seems feasible then I could certainly use some help with the methodology Kevin so you will regret passing that email address on!

I have enjoyed re-reading Frederick' posts tonight and think that both methods make sense to a degree.

Kind Regards,
Athol

 

Dear Athol, Kevin

I have trialled different length cranks on myself, and liked it. Then I tried it on some junior racers who seemed to prefer it as well. Then senior racers. We never measured output because the Olympic Training Centre had moved from my area by then.

However, what's nice about studying biking is that it's easier to set up a real world test on rollers, whereas with runners, skiers, etc. it's much more difficult.

Also, bikers are much more likely to be technogeeks (not meant to be disparaging) and understand, and even like the process.

Because biking is an extremely repetitive, high stress exercise, small biomechanical differences can often be noticed by the riders, and as I said previously, they are much more likely to be attentive to these slight symptomatic differences. Not as reliable as physiological measures, but certainly a part of any study.

If you have any questions, please do not hesitate.

Cheers

Frederick

 

Interesting perspective Frederick. I had heard of your method but never gave it enough thought before. I suppose the short crank would be less noticeable on the recovery stroke at the top with an LLD. In terms of power it could make a less significant difference than we are suggesting but we don't really know that for certain yet.? In all though if cyclists prefer it......keeping an open mind!

I've enjoyed this thread, cycling is a passion of mine (although a recent event has kept me sidelined for the past two months). :craig:

I'm looking forward to Athol's research.

Regards,

 

Athol don´t know if this helps or not with Power studys - but to make it more realistic and in different conditions - ie flat, hills etc - weather maybe these new Pedal power meters might be something to consider.

left v´s right, long v´s short crank arm, normal v´s shim - power metered

http://roadcyclinguk.com/news/gear-news/garmin-vector-power-measuring-pedals-released.html

 

Cheers Mike.

I'll check them out.

Regards,
Athol

 

I've located a study subject for the research:

 

Reviewed: Solestar, Footbalance orthotics

 

The impact of carbon insoles in cycling on performance in the Wingate Anaerobic Test.
Michael Koch, Michael Fröhlich, Eike Emrich, Axel Urhausen
Journal of Science and Cycling, 2(2): 2-5 Page 3 2013

 

Cycling performance enhancement and injury prevention use an arch support insole with forefoot wedge
Sai-Wei Yang1, Po-Hsun Li and Keh-Tao Liu
Journal of Foot and Ankle Research 2014, 7(Suppl 1):A102 doi:10.1186/1757-1146-7-S1-A102

 

From April LER:
Cyclists and foot orthoses: A unique set of challenges

 

The effect of foot orthoses and in-shoe wedges during cycling: a systematic review
Boon K Yeo and Daniel R Bonanno
Journal of Foot and Ankle Research 2014, 7:31 doi:10.1186/1757-1146-7-31

 

Orthotic Insoles Show no Acute Effects on Knee Kinematics during Pedaling in Experienced Cyclists
Elise C. Caldwell, Amos Cole Meyers, Jordan Hirsch, Moataz Eltoukhy, Ryan Pohlig, Joseph Signorile. University of Miami, Coral Gables, FL.
Presented at the ACSM Meeting; San Diego May 2015

 

I was a co-author on some research on knee joint loads during cycling back in the early 1990's with the University of California, Davis, Department of Mechanical Engineering. We found that forefoot to pedal relationship in the frontal plane, subtalar joint axis location and a few other variables significantly affected knee joint loads during seated cycling. We used a "force-pedal" that allowed knee joint kinetics to be calculated.

I would imagine that studying only knee kinematics (and not kinetics) during cycling is about as helpful at determining knee injury mechanisms during cycling as is studying only knee joint kinematics (and not kinetics) in walking and running is helpful at determining knee injury mechanisms during walking and running.

In other words, be suspicious of cycling studies that only look at knee joint kinematics and don't attempt to determine knee joint kinetics.

http://www.ncbi.nlm.nih.gov/pubmed/1400519