Juan Foote

I have been wondering about something and figured there were enough people with a common injury to give me an opinion on the subject.

As an LBKA I have considerable strength differences in my legs. For the first couple of years I rode using one leg for 99% of my power and the residual was mostly just riding along. I developed some knee issues in my good leg after a while from doing that and decided to try ramping up the use of the other leg. That led to it's own set of issues with prosthesis fit, which I worked out with my fitter over the course of the last year and a half or so. I am now at a point where cycling is actually less painful for me than walking, but have come across a new challenge that I need some insight on.

I realize that no matter what I do it will be extremely hard to get anywhere near the strength in my residual as my other leg. Since starting to use the legs more equally I have strengthened it considerably and have been able to eliminate the issues in my good leg. I have noted, increasingly as of late, that I am starting to have a pretty fair amount of pain in my lower back on the residual side that I don't recall having before. I am climbing better, riding farther, and paying more when I get in....

At what level do others in this situation use the residual? Do you encounter problems when you pass a certain threshold? If so, what have you done in order to eliminate those problems?

AlbertaBeef

I'm not an amputee, but do have spinal-stenosis that affects my left side - the nerve impingement causes strength loss. I also end up with back pain above the point of my stenosis after I started really pushing it.

My physio thinks it's due to recruiting other muscles - when cycling you use not just quads, but all the muscles of your legs, glutes and lower back. In my case, my physio is pretty certain that my other muscles are being recruited on the left side to help do the work that they leg can't do, and as such I end up with soreness.

I found two things work - trying to constantly self-monitor, and backing-off a little when the threshold increases (I used to just block out the pain until it hurt like a bugger) or spinning faster in a lower gear. For me the most-important is simply to cycle - I'd rather go a little slower and enjoy my time out. When it is about speed though, I simply bite the bullet and take an extra recovery day.

Juan Foote

Thanks for your post, I think I have figured out my issue based upon searching some of the issues you brought up. I suspect I have sacroiliac joint dysfunction. It is apparently quite common among lower limb amputees and up to this point not a single person (doctor) I have gone to see about it has mentioned it.

kleonin

I'm an RAKA, so it's nearly impossible for me to ride an un-adapted bike. Finally, I just decided to go with a handcycle.

Juan Foote

I had considered a recumbent trike, but am really glad I didn't decide to do it simply from a room to keep the bike. In my current rental it would have had to stay outside and would likely already have been stolen by someone with no clue what they were getting, just to do it. I have invested a lot of time, money, and effort into riding a standard bike and certainly am not about to give up now.

Juan Foote

What about using different leg lengths?

I know that it is bad for me to walk in a leg with a different length. That prosthesis are typically just short of the other leg in order to avoid "carpet drag" (toe drop) from having no ankle flexion.

I adjusted my riding leg (different device than my walking leg, an older leg that we have modified) to be a bit longer than my leg. I had done this to avoid a knee issue I was having upon extension. If I bend me knee to a certain point and then straighten it past a certain point, it will snap/crack right at extension. If I bend it just a little more and not straighten it so much, it won't. IIRC from my fit I had one leg extending to around 35* and the other leg at 40~*
This would create a different motion in both sides of my hip. So I guess I have to do a little trial and error to see what I can do with shortening that leg and keep track of what happens when I do.

Tom Stormcrowe

This might sound like a truly weird suggestion, punkn, but have you considered making a leg that's length adjustable with 2 stops, one for riding and one for walking? It'd be fairly straightforward as an engineering problem. Use a screwdrive and adjustable limiters, and you could even get fancy with motor powered operation with micromotors and a small L-ion battery or even EverReady batteries.

proileri

I'm afraid I don't know much what kind of therapy you've gone through for the leg, but have you tried to focus on the weaker leg strength doing one-legged gym exercises? I'm thinking a multi-hip machine would probably be the best device for that, as it doesn't put any load below the knee.

Juan Foote

Tom, I actually acquired an adjustable pylon for use on my cycling leg just for this ability. It has a set screw and is marked for height. Loosen the screw, twist the pylon up or down for extension/retraction. I was talking to my prosthesist about it today, and it seems that even with very little walking, but many days a week riding like I was doing when this problem first presented, would aggravate this issue. Going to a chiro would do wonders, but don't have the extra cash for it right now, so I am trying a DIY approach. I have solved (and created) my own issues so far this way, with a bit of help, and will see what I can do now.

Juan Foote

I shortened my riding leg by a bit over 1/2", as close as I could make it by eye. It seems to have helped some with the hip and lower back pain I was experiencing, but is still a bit too early to tell. I have been able to ride quite a bit more since doing so, four out of five days this week so far.

esther-L

One of the things that physical therapy is working on me, is sacro-iliac issue. This is directly related to difference in strengths in my 2 legs. PT is working on me to get a smaller strength difference. There are 2 exercises that you can do with someone helping you, which move the sacrum back into the right place.

Some amputees use a crank shortener on the prosthetic side. The effective leg length is a bit shorter on the prosthetic side, because the ankle does not bend while pedaling. You may want to look for a good bike fitter. I learned at my last bike fit that my hips move unevenly while I am pedaling.

I need to do a lot of hamstring stretching, because tight hamstrings pull on what's connected, and add to lower back pain.

I am not biking very much right now, getting PT for my IT band pain.

Juan Foote

I dealt with the IT band issue through some stretches. I try to find solutions to my own issues as one, I really don't have the money to go to PT with every problem I have, and two, my experience in the past has been that I commonly do more on my own and accomplish more than their programs do.
I would be very interested in knowing what these two exercises are that you are doing to help with that sacro pain.

As to the hip thing...It has been suggested to me quite a few various solutions to the leg discrepancy. I cannot logically see how I can correct a leg strength issue by shortening the lever length on the weak leg. It was recommended that I do away with my foot for the cycling leg, but found that I don't have enough rotational strength to unclip without it. I have purposefully been riding with a longer than normal riding leg. Since shortening it, my lower back pain seems to be getting better, along with some other bad habits I was doing...like standing only on the good leg, things like that. I have had, and constantly work with a professional fitter..one of the perks of working at a bike shop, and am constantly looking for better ways to peddle and thus correct my hip motion towards proper. I have done the same with my walking...for the most part, with jeans on, it would take a trained eye to see the mechanical issues I have with gait. I have studied the mechanics of gait quite a lot and have made corrections in order to appear and "work" as naturally as possible.

benajah

One way I found to get both legs at at least close to the same strength is to climb, and climb a lot. Climbing doesn't allow you to "cheat" and have your good leg do most of the work, so your amputated side simply has to pull its own weight. Enough climbing training and the discrepancy can be somewhat corrected. Much like doing squats at the gym, where you have to do one legged squats to make sure the amputated sides getting a workout.
Then again, it requires you to have access to good climbing areas. Where I live in the SF Bay area this is easy, as riding basically here is climbing long hills then riding down the other side. I get a better workout now cause I'm fat since my kid was born.

Juan Foote

Around here are "rollers", nothing most would call a climb, but certainly not flat. Up until recently I had been avoiding all but the flattest routes with the shortest and easiest climbs. I swapped out my RD and cassette not long ago to something with a wider range and have been looking for the climbs to help improve my ability. I am at a point now where I am considering putting the original RD and cassette back on, since I am running out of gear on the faster paced club rides and very rarely, if ever, using the top two cogs.

benajah

You should. One thing I have realized since losing my leg is that in terms of cycling power, a bk amputee, in order to avoid "cheating" almost has to set things up in training to be as difficult as possible. Steepest climbs, narrowest gear ranges...removing the small chainring and front dérailleur from your bike and staying in the large ring. The trick to keeping the amputated leg in shape is to remove the opportunity to cheat.
in fact, if all you have is rollers, staying on the large ring might be a key.

Juan Foote

I can certainly see where doing so would help with correcting the weak leg. I have to balance that with care for the damaged knee on that side as well. My original injury had caused a great deal of damage to the knee joint itself and surgery was planned in order to straighten some things out. It turned out I was unable to move forward due to an infection of the residual, and by the time we could operate it would have required a "re" break of the knee joint to then fix it.
By this time I was already test fitting for my check socket. Going through another surgery was going to make all that worthless, aside from the fact that I hadn't tried to walk on the bad knee yet. It turned out that, in spite of the damage, the knee was operational enough that my ortho suggested I just use it till it blew out and then have the (same) surgery to fix it. His words were that once you operate, it's never the same anyway, so go with what you got.
The end result is that with a great deal of work my knee is actually pretty smooth so long as I don't put power on at certain points I have learned, lest it pops and hurts like hell, and not to use too much quad.

benajah

Yeah it's always tricky. It would be great if ther were easy answers huh? Unfortunately there are so few of us, and we all have such unique issues that it's almost like every person just has to learn from experimentation what works and doesn't.
i was a competitive racer before I got hurt, and have gotten back into racing a few times since, but I simply can't hang with able bodied guys and get discouraged, then overtrain and always seem to hurt myself. But there aren't any amputee racers local to compete with.

lostforawhile

this is a very interesting thread, I'm helping my wife get into riding and she has the same weak leg issues, she had a tumor removed from her spine as a baby, and it made a mess of it, she also has one leg much weaker then the other, without much feeling in one foot, the main issue I am having to help her overcome is her foot doesn't face straight forward on her right leg, it turns to one side and has a tendency to fall off of the pedal, I'm trying to locate a crank for her bike she has now I can modify it to turn the pedal canted slightly outward, I'll press a piece of steel in the threaded hole for the pedal, weld it in place, then machine the pedal threads at an angle, so the pedal installs "crooked" this will place her foot directly on the pedal,while still allowing it to rotate

qcpmsame 

Lostforawhile,
For the canted pedal for your wife, couldn't you use one of the aftermarket pedal extensions and have a machinist put the degree of cant into the threaded end of the extension, where it meets the pedal's threaded end? They could properly bend the extension's barrel. I don't know how many degrees her foot is turned out so I can't say for certain the extension is long enough but I imagine they might well help you without having to weld on to the crank and maintain the integrity and mechanism of the crank arm so it would be strong and not fail (I do realize this is not your concern, your wife's being able to ride comfortably is paramount, and it should be. I was thinking safety and failure from heat that may show up later.) The extension would put any clearance you need for the foot's cant outwards and prevent her hitting the crank arm with her heel. The extensions aren't very expensive, IIRC, I see them on eBay and some of the on-line stores, I imagine an LBS could get them quickly.

This is just a thought from an inveterate engineer that sees something that needs solving to make a person's life better, but I think this is the same principal you are talking about and would be less expensive as far as machinist cost. If you were in Pensacola I have a master machinist/master welder that I could get to design and fabricate this, easily suing the extension or by machining an adapter for gratis. Best of luck in finding her a means to solve the problem and if I could help in any way please P.M. me, anytime.

Bill

Juan Foote

I agree, look at a pedal extension and personally would consider going clipless. As an amputee there is no way to keep the foot centered on platform style pedals. Having the foot retained in position is a plus that cannot be ignored. In my particular case I cannot unclip that foot while riding either, so I have taken steps to learn how to stop (etc) only using the "good" leg. Any issues that you run across, post in this forum; there are a LOT of helpful people here now.

lostforawhile

I am a machinist, I'm just trying to figure out exactly what would work, the crank end wouldn't be weak as the cast part of the crank itself wouldn't be changed, I would just be welding in a threaded insert into where the original pedal threads went, this is a cheap bike, but it is low to the ground and works for her, I guess I could upgrade it's components over time, the frame is good, but everything else is cheap. then I know I'm sticking with a frame she can use

qcpmsame 

LFAW,
See your thread about the crank set, please.

Bill