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I encountered a person with a disability in one leg. They are unable to control their ankle/heel movement. They are unable to maintain their foot parallel to the floor at the top of the pedal stroke (see picture). Their foot position means they are unable to get power to the crankset.

issue and position due p. condition

what type of solution can be the good one? After searching in internet i've found some products but i have no clue about this matter.

  • just a leg/ankle prosthesis inside the clip shoe?
  • a Shortener on this side?
  • a swing crank?
  • a Pendulum crank?
  • a Self Levelling Foot Sandal/pedal?
  • other alternatives?

pedal w calf fixation pedal w calf fixation weighted and ankle fixation pendulum crank

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  • It would help to know whether 1. this applies to one leg or both and 2. whether a handcycle is a possible solution given their expense and recumbent nature.
    – Nathan Knutson
    Commented Sep 1, 2022 at 19:01
  • it applies only to one leg (the right one on the picture). A hand cycle/trike is not on the roadmap
    – Daniel Perez
    Commented Sep 1, 2022 at 19:17
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    Not sure what sort of pedal you've got there but without going to adaptive, would using standard clip in pedals be an option?
    – Hursey
    Commented Sep 1, 2022 at 22:01
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    @Weiwen Ng the person is very limited about controlling the right leg, i.e the heel/foot tends to don't be horizontal with the floor (see picture) and this position not only doesn't help to spin the crankset but also can damage the foot/heel. A MTB clip pedal is being used to keep the foot t attached the pedal
    – Daniel Perez
    Commented Sep 7, 2022 at 16:08
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    Is the rider able to wear a boot that goes up the ankle to restrain it in position? Like a stiff jackboot or a small moonboot?
    – Criggie ♦
    Commented Sep 7, 2022 at 21:28

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I did a quick google image search for the terms "cycling leg prosthesis", And I see two main trends in the pictures: Some rides appear with prosthesis that have a foot, and seem to simply use a regular pedal. Others appear to use a "footless" prosthesis that seem to clip directly to a normal pedal.

These two findings make me think that: 1) A helping support that would keep the ankle angle constant can be made strong enough to pedal, so the supports you added to the post are on the correct track. and 2) A person can pedal without a foot, by pressing the pedals directly bellow the ankle.

Maybe this 2nd point helps in this case, the reason being if you pedal with the heel, there is little torque trying to bend the ankle upward. This would also reduce the required "offset" in height between the two cranks.

I have seen people using different length cranks in the same bike, but never talked to them to learn more.

In my search, this video popped up and you may find it interesting. (not a product rec)

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