Tech & Wearables

Technical FAQ: Solutions for those with different length feet

A dual-sided power meter may be helpful in determining differences in left-right power production.

Dear Lennard,
My question is about cleat stagger for riders with mismated shoe sizes. I was born with a leg-length discrepancy of ¾-inch that was corrected surgically to within 0.1 inch (femur top-to-tibia bottom) but I still have a 32mm difference in foot length (R smaller). I have custom road shoes and am wondering what the current thinking is on cleat position for this situation. My old shoe setup has the heel-to-cleat center distance approximately the same (L 170mm, R 164mm), which makes the lever arms very similar but has the effect of changing the cleat position relatively on each foot (i.e. the left cleat is farther back/behind the ball of the foot) and the right farther forward (at front of the ball of the foot). I am working to recover from L-side high hamstring tendinopathy that appears to have R-side glute weakness as a contributor and am wondering if this cleat setup is a potential source. As I had this cleat arrangement set up 10 years ago, I’d like to know if the thinking of the fit community has evolved and a different approach to my new shoes is recommended.

Thanks for any help you can provide. As a side note, I found your comments on your own high hamstring tendinopathy and recovery from your Meld 3D saddle review very helpful. Has that continued to be a good saddle for you? I am considering this as part of my recovery scheme if I can’t find another stock saddle that works.
— Mike

A custom Meld 3D saddle can be shaped perfectly for one’s hamstrings, allowing room for them to swing up and down without impingement. Photo: Lennard Zinn

Dear Mike,
It’s great that you got that huge ¾-inch leg length discrepancy corrected. You still have plenty to deal with, since foot length discrepancy of 32mm (over 1¼ inches) is enormous. Your legs are now exactly the same length from heel to hip, but they are not on the bike, since the length of the foot from heel to pedal contact is part of the leg length as far as the bike is concerned.

In answer to your hamstring question, yes, that saddle has continued to work for me.

Here are responses from a number of experts to your question that will give you some ways to address that hamstring tendinopathy. Good luck with it; hamstrings can take a long time to heal. I yanked my other hamstring skiing in January and have been back to rehabbing my right one after my left one finally healed after a year and a half.
― Lennard

From fit guru Andy Pruitt Ed.D., originator of 3D video capture for bike fitting and a number of fit systems and fitting education:
Since the leg length discrepancy was corrected surgically, that doesn’t need to be addressed! In my experience, we usually have success setting cleat position on the short foot just at or just behind the ball of the foot. Then measure from the heel to the center of the clear and match that cleat position on the long foot shoe! This gives you the same length foot level bilaterally. If this results in the cleat too far into the arch area of the long foot, then cheat it forward a millimeter at a time until you feel good! But give it a chance! Asymmetrical cleat position is used for femoral leg length discrepancy, not foot length!
— Andy Pruitt

RELATED: Andy Pruitt’s Complete Medical Guide for Cyclists

 

Retul Bike Fit
Photo: Retul

From Todd Carver, founder of ReTül Fitting System:
Wow, now that is a lot going on. But boiling it down to the left hamstring injury, and the possibility that is being caused by overextension.

1. His tight right glute could be causing him to rotate towards the right.
2. His shorter right foot lever could be causing him to reach more for the pedal at the bottom of the stroke.

Both of these could cause a right-side forward rotation that would put stress on the left hamstring due to overextension.

A quick trial could be to move the right cleat further forward (if he can tolerate this), or adding a lift between the cleat and shoe. Both of these would, in theory, push him back over the left side of the bike, reducing the overextension.
— Todd Carver

From Jason Williams, a fitter at Specialized Performance Center/ReTül Development Center:
It sounds like his current (10-year-old) set up is a reasonable compromise. His leg length (not including foot length) has been corrected, so a normalized cleat position relative to heel makes sense, but often that significant offset feel under the ball of the foot can be problematic. A slight stagger to the cleats can help normalize the feel under the foot.

Of course, it is always hard to say without seeing him in person on the bike, but here are some observations that come to mind.

The 6mm offset cleat placement could be leading to the asymmetric pressure and irritation at the sit-bone/upper-hamstring, though, as he points out, the right-side glute weakness also plays a role. Asymmetric glute weakness can cause a rotation on the saddle.

The 6mm additional length on the left side could be pushing left sit bone/hamstring up onto the saddle more than the right. The shorter right side may be pulled off the side of the saddle causing him to load the left side more prominently

If I were to make a change, I would see if there is an option to move the left cleat back farther to match the right side – 164 mm from heel. I would not recommend taking the right side forward as it is already forward of the ball of his foot on that side.
— Jason Williams
Sports Scientist, Human Performance-Retül

A power meter with a detailed analysis of pedaling forces, including left and right foot monitoring, and force vector readouts may be helpful in determining differences in left-right power production. Photo: Dan Cavallari

From bikefitting.com/Shimano/PRO/Pearl Izumi:
The logic for this rider’s cleat setup makes sense, given his unique situation. Has the rider been able to assess output with a dual-sided power meter? It would be interesting to see any difference in power production from the two legs, as I wonder if there is a correlation to his left-side high hamstring tendinopathy. If I were to guess, the left side of his body is doing the majority of the work, which can lead to discomfort and injury.

Adjustments to consider would be moving to shorter crankarms to reduce the total range of motion of lower extremities, as well as reducing total extension at pedal stroke bottom dead center which may lessen pressure on the hamstrings.

Given his circumstances, I would guess that continuing to ride while managing discomfort requires significant ongoing investment in off-bike strengthening, stretching, and consistent bodywork. Kudos to him for keeping his body moving.
—Chris Jacobson
Product Manager
Pro Bike Gear | bikefitting.com


Lennard Zinn, our longtime technical writer, joined VeloNews in 1987. He is also a custom frame builder (www.zinncycles.com) and purveyor of non-custom huge bikes (bikeclydesdale.com), a former U.S. national team rider, co-author of “The Haywire Heart,” and author of many bicycle books including “Zinn and the Art of Road Bike Maintenance,” “DVD, as well as “Zinn and the Art of Triathlon Bikes” and “Zinn’s Cycling Primer: Maintenance Tips and Skill Building for Cyclists.” He holds a bachelor’s in physics from Colorado College.

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