Leg length discrepancy
 

I bought a road bike last fall to supplement my mountain bike, and I average about 120 miles per week, sometimes more. I am in pretty good shape (6 foot, 165 pounds) and I’m a fairly strong rider.

Anyways, I’ve noticed that the muscles in the back of leg (just above and below the knee) are sometimes sore after a ride, like my seat is too high, but only in the right leg. I lowered my seat a little and it helped, but any lower and it will be uncomfortably low. Still, no matter what I do, my right leg is the only leg that feels soreness. Additionally, my right lower back starts to feel tired after an hour or so, and it’s never my left lower back. I got a shorter stem, and it reduced the discomfort in my back, but it’s still there somewhat, and only on the right side.

When I’m pedaling, I can’t help but feel a sensation that my right leg is slightly shorter. Therefore, I bought a cleat ship kit. However, I just want to make sure my symptoms are consistent with a right leg that is slightly shorter and not a case where a shorter left leg would cause right side problems.

I really want to get this figured out because I have the fitness to do long rides and I’d like to be able to do 100 mile rides without feeling this discomfort.

Thanks,

John

If you have insurance, have you considered letting a PT check you out? They have the tools to tell you what the problem is and how much discrepancy there might be.

It's very simple to figure that out. Simply use the heel-on-pedal test with each leg. That'll tell you. I have one leg that's much shorter than the other, so I shimmed the cleat on the short leg, though that's still not enough. The problem with shimming cleats a lot is that then your knee comes up higher, too, so that's still not optimal. Optimal would be a shorter crankarm on the short leg side. I'm not motivated enough by any problem to bother with that.

Thanks for the help! I’m only 17, but my parents have insurance so a PT is an option. I’m mainly wondering if a shorter right leg would cause right side lower back pain or if it would cause pain on the opposite side of the shorter leg.

I'm not sure a shorter crank arm on the offending side is the answer. No only is the length disparity accentuated, but now the short leg & long leg doing are doing a different amount of work by way of travelling different distances along the circumpherence of the crank rotation. This surely would result is a strength disparity very soon.

I think step one is figure out how each leg was different first. Heel to knee? Knee to hip? Are both feet the same size? Then proceeding accordingly. An insole on one shoe or a shim (or both) would get the legs the same length. Turning the seat a degree or 2 could get some symmetry if your femurs are different. Adjusting cleat position could be the answer for different sized feet or leg length.

I had hip issues. After lots of physical therapy for my psoas tendon. My left hip always gave me trouble but improved. Switching to smaller 170mm cranks solved part of the issue by limiting the size of the pedal circle. Combined with a shock absorbing seat post that I leave the "lock out" nut loose so that it turns left & right a few degrees with every stroke completly solved it. I could tighten it, but it's designed to engage or disengage the shock absorbing function. That it has a few degrees of clockwise/anticlockwise slop is a happy coincidence.

It turns out that an MRI showed a bony protrusion in my hip and the psoas tendon was snapping across it with every pedal stroke. The smaller crankset & different seat post meant it didn't snap back & forth any more.

My guess is (& it's completely a guess) that whatever the issue it is not being helped by a lack of flexability. Cyclists then do have tight hip flexors, short psoas, limited IT band flexability, and short strong glute/hamstrings. All of which make for back pain. Older cyclists just get a shorter stem & ride more upright rather than stretch. Too bad, they could regain lots of speed from their youth if they'd take on a stretching routine.

Good luck :)

Heel on pedal method explained here: How to Find Your Ideal Saddle Height - I Love Bicycling
In 5 minutes, you'll know which leg is shorter, if that is indeed the issue.

It can. But so can other things, and if you make some change to your bike and you don't have a length discrepancy it might make you even more sore.

things that have been done before 1 crank arm shorter, or build up 1 pedal ..

pedal one will be an oval motion, shorter at top & bottom , arm still as long thru the power stroke ..

My left leg is slightly longer than the right, so I adjust by putting the left cleat further back on the shoe. That means my left foot is always a little further "out" than the other, and I can then set the saddle to a position that works for both legs. If the difference were any greater, I'd be throwing in other tricks to make things work out.