An Incomplete Guide to Bicycling for Amputees

(But as complete as I can make it)

Joe Sapere

This guide has been written by Joe Sapere based on his experiences in riding a bicycle as a Below the Knee (BK) amputee. Joe is not a professional rider. Nor is he a super athlete. Demographically, he fits about in the middle of the amputee population. He is upper middle aged (66 years), slightly overweight, slightly out of shape (though round is a shape), and certainly not capable of running a triathlon. He is just an ordinary person who has occasionally ridden bicycles for pleasure all of his life. Since his accident and subsequent amputation in 2000, riding a bicycle has become his primary form of rehabilitation, recreation, and physical activity.

Joe founded a non profit organization called Amputees Across America and for the past five years, starting in 2002, Joe has ridden with three other amputees across the country, riding on a recreational basis to demonstrate to others that he rides bicycles because he "can" and because it is a form of low impact exercise and recreation that is available to all amputees with little or no adaptations. Hopefully, this guide will serve to encourage amputees to take up the bicycle as a form of recreation, physical conditioning, and rehabilitation. The guide is not all inclusive, but addresses some of the issues that have been encountered while on the ride.

Riding in a group with sag wagon blocking:

Loss of ankle and foot flexion with prosthetic foot (inability to point the toe).

Loss of calf muscle. The muscle is still there but not connected to anything so the muscle exerts no force on the pedal.

Combined loss of the ankle and calf muscle equates generally to a 20 percent reduction in pedal force on the side of the residual limb (stump for dummies).

As the residual limb loses volume while riding, the prosthetic leg tends to rotate outward causing the heel to strike the crank.

Inability to rotate the prosthetic leg. This also inhibits the ability of the rider to easily unclip from his pedals in a timely fashion.

Because of the lack of foot flexion, an amputee cannot stand on the pedals because he is not able to force the pedal past the top dead center of the stroke.

According to most AK amputees, a BK has but a flesh wound. This is probably true since having an AK, the loss of power and the energy required to just walk increases exponentially with the loss of a knee. For this reason, the AK will suffer all of the limits of the BK as described above but also:

Inability to step down on to the pedal to dismount. Most of us just step down on the pedal with the right or left leg and then when the bicycle comes to a complete stop, we step down onto the ground with the other foot. Not so with an AK. The knee on his prosthetic leg is freely swinging so that he doesn’t have to move his leg against the pressure of the hydraulics in his knee. This is fine while pedaling but if he tries to dismount by stepping down onto the pedal, and then the ground, his leg will buckle under him (remember it is in a swing free mode).

Loss of the foot, ankle, calf, and limited force from the thigh, an AK will suffer a loss of approximately 80 percent of the pedal force on his affected side.

Though the average amputee can mount a bicycle and ride it with no adaptations, the following have been useful to improve the mobility, comfort, and safety of the riders.

Inability to point the toe (AK and BK): Put a shorter crank on the prosthetic side. I have a 75mm crank on my good side and a 65mm crank on my prosthetic side.

BMX pedal. Wearing a sneaker, the little nibs provided plenty of friction to hold your foot on the pedal. This works fine for a BK but not for an AK.

BMX pedal with a strap or a cage works fine for an AK. It holds his foot securely but allows him to easily exit and put his foot down when stopping.

Clips:

BMX pedal with heel cradles. For a recumbent or trike: Because of the high foot position, a BMX pedal by itself or with a cage/strap will not secure the foot safely enough to keep it from sliding off the pedal and impacting the ground. The cradle allows for easy foot placement on the start and prevents the foot from falling off of the pedal.

The cradle is fashioned from a water bottle cage, a BMX pedal with the reflector in front and back, two pieces of aluminum strips (found in any hardware store), a nut and a bolt.

Step 1: Cut off the end of the narrowest part of the bottle cage so that you have the two ends sticking out like a pair of knitting needles.

Step 2. Cut two aluminum strips so that they will fit cross ways inside the pedal to act as a clamp.

Step 3 Drill a single hole in the aluminum that is large enough to pass the bolt through.

Step 4 The reflector is attached by two plastic prongs that are seated in two holes. Remove the rear reflector from the pedal.

Step 5 Fit the two prongs (or knitting needles of the cage) into these two holes. You may have to drill out the holes just a bit if the fit is too tight.

Step 6 Fit one aluminum plate inside the cavity of the pedal on top of the two prongs of the cage. Fit the other on the bottom of the pedal. Place the bolt down through the hole in the plate. Attach the nut and tighten. This will clamp the prongs and prevent them from pulling out.

Step 7 Bend the other end of the bottle cage to conform to your heel.

AK inability to dismount via pedal step down: On a road/MTB, lower seat height to dismount to the ground without stepping down on the pedal. On a recumbent or trike this is not an issue.

Bilateral BK (Double amputee below the knee): All BK adaptations seem to work. Not a significant problem.

Bilateral AK: I am not sure how this would work on an upright bike. Probably a trike would be the only option and riding at a pace commensurate with limited power on the pedal strokes. Consideration should be given to a hand powered bike.

Little need for adaptation for a BK.

A lower seat position for an AK so that he can dismount to the ground.

BMX pedals work fine for a BK

BMX pedals with either a cage or a strap work fine for AKs and BKs

Clips work but with major disadvantages

Rotor Cranks or Q Rings

Pedal extensions

Shorter crank length on prosthetic side

Balance not an issue. Stable platform

Able to start from a stop on an uphill incline

Ease in starting and stopping. Transition to placing both feet on pedals is smooth

Heavier than road and two wheeled recumbent bikes. Slower performance. Energy requirement is greater than other bikes.

Very comfortable.

Can use heel cradles or clips

Harder for vehicular transport

Harder to ride in traffic due to wheel base width (you stick out more into the line of traffic)

Harder to ride on shoulders particularly ones that are narrow or have rumble strips in the middle of their surface.

Rotor Cranks or Q Rings

Pedal extensions

Crank lengths

Recumbents: Two wheeled like the Bacchetta ( www. bacchettabikes.com ) . Suitable for touring, commuting, and recreation.

Performance and comfort far surpasses that of both Trikes and upright bikes.

Has same advantages as upright in riding narrow shouldered roads

Transport not a problem

BMX pedals with heel cradle is a necessity

Somewhat more challenging to get started. An amputee lacks the strength required to place his prosthetic foot in the pedal and start pedaling, bringing his good foot up onto the other pedal and continuing the stroke in a smooth manner. With his good foot on the pedal, it takes a bit longer to getting the prosthetic foot onto the pedal, consequently, continuing the pedal stroke is not as smooth.

Different balance than an upright, particularly at slow speeds. Balance may be an issue at first but the learning curve is not uncomfortably steep.

Long uphill capability invokes a penalty in energy, balance, and performance. Bicycle tends to wobble at speed lower than 5 mph. Energy management minimizes this problem by entering the hill at a speed greater than an upright until you run out of speed and energy. Then granny gear at a speed greater than 6 mph.

You are not going to be able to begin pedaling from a standing start on the middle of a steep hill. If this is the case, then I am not too proud to walk the bike up the hill or catch a ride. I will more than make up for it on the downhill side.

Rotor Cranks or Q-rings

Pedal extensions

Crank lengths appropriate