Jason commented on my previous post about his desire to tackle the Alpine challenge. Jason is a below the knee amputee as well.
The Alpine - that's awesome!! No way I could imagine doing that at this stage. I wrote about coaching a rider who did the Alpine a couple of years ago in these two posts.
You go Jason!
So, in summary, have a look at these posts which show my cycling leg set up in a little more detail:
My new leg and socket design
How my cycling leg attachment works
The cycling cleat attachment and adapter plate
The urethane adapter to provide lateral roll for out of saddle efforts
My prosthetics guy made my everyday walking leg socket with quite a shallow rear cut away with cycling in mind. The rear of the socket is such that I am able to pedal with a full length crank.
But remember I have the cleat directly at end of the pylon and so the knee doesn't need to bend quite as much as if the cleat was positioned further forward simulating an "under the ball of foot" position.
The socket also has some funky design at the front.
The other adaptation I haven't shown in pics is some soft foam-like material I place at the front of the stump below the knee, in-between the sock and liner, so that it fills the gap between the stump and top front of the socket when you are pedalling. Bend your knee when sitting and you can put your hand/fingers into the largish gap that forms betwen the stump and socket.
The gap isn't there when standing up of course but with the knee constantly bent on the bike, I found filling that gap really helped with power production and provides a much more secure feeling. I just got some off-cuts from a Clark Rubber store.
As my prosthetics guy says, the aim is to maximise the contact surface area between stump and socket. That will be something we look at when designing a dedicated bike leg socket.
Eventually I intend to have a dedicated socket / cycling leg made, however before that happens I need to further strengthen my hip so that the lateral offset of my "foot" can be brought a little more in line with the hip and knee.
For a permanent cycling leg, I envisage something like what Jody Cundy of Team GB paracycling squad had made. Anyone who can do a 65 second kilo sure has a leg that works!
See this item for more details:
Jody Cundy Interview
In there you'll see his new (the carbon leg) and old leg set ups. I don't expect to have my cleat positioned as far forward as Jody has his - he simply replicated what he was used to with his prior set up when wearing a cycling shoe over a prosthetic foot.
The one thing you have to consider with a direct cleat to pylon arrangement is that you can't walk on it. So logistics becomes a factor when planning on going for a ride.
Another thing I've noticed, since I have more than one bike, is that I am now much more sensitive to the different Q-factors of the cranks on my bikes - to the extent that I need to alter the angle of the prosthetic cleat attachment in order to ride a bike with different cranks. My two road bikes have 175 mm Campagnolo cranks however one is a Record crankset and the other a Chorus model and they have different Q-factors.
I never realised until now how much the ankles do the job for us, managing all the lateral roll when out of the saddle and coping with the small differences in positional set up.
What did Joni Mitchell say to us in that Big Yellow Taxi song?
Don't it always seem to go
That you dont know what you've got
Till its gone....
No parking lots here though!
If you want to drop me a line, just use:
alex A T cyclecoach D O T com
Anyway Jason, good luck with it!