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Cycling is well regarded as an alternative form of excercise for lower limb amputees due to its ability to utilise all lower limbs regardless of residual limb length.
Whether you are on a mountain bike on a lightweight road bike there are a few considerations to be contemplated before riding a bike.
If you have riden prior to your amputation you already have the motor skills needed to ride post amputation, all you have to do is gain the confidence and possibly adapt the bike in minor ways to your prosthesis or lack of prosthesis for higher levels of amputation. If you have never riden before welcome to the world of bike riding, hope the following helps you on your way.
To use a prosthesis or not:
Actually the use of a prosthesis for bike riding really depends on your level of amputation. I recomend that all lower limb amps except for exceptional short AK's and hemi's DO use a prosthesis. Although it maybe difficult and your sound side does all the work, in fact excercising the prosthetic side in beneficial to the development of muscle in the residual limb.
The only lower limb amputees that would not benefit from using a prosthetic limb are those who do not have enough physical strength in their residual limb to physically push the pedal. However, this is not to say mid-thigh AK's should not contemplate riding without a prosthesis, but it should an alternative after all else fails with using a prosthesis. Of course those AK's who do not use a prosthesis for daily activity will no doubt prefer to ride without a prosthesis.
Balance: & Confidence
As you have now discovered as a new or recent amputee many of your former motor skills need a little revision, such a re-establishing your balance for swimming and other physical actiivities. Cycling is no different, your balance on the bike will be different than when you had two full limbs and the higher the level of amputation the more difference you will find.
Essentially, setting yourself up on your bike is the same as when you set up the bike prior to limb loss.
a. Frame Size: Make sure the frame size is correct for your height. You may feel a little more comfortable on a frame slightly smaller than what is recomended for your height, that is OK. Frame size is measured from the centre of the bottom bracket (the nut that holds on the pedal) to the top of the seat tube(where the frame ends and the seat begins). The best way to find the right height is to stand flat footed over the frame. The clearance from the crotch to the frame should be about 2cm- 4cm or .5 to 1inch for a road bike and 6-10cm for moutain bikes. Keep in mind that peoples proportions are different as are bike frames, the distance from the seat to the handlebars is also a consideration. Typically a six foot man should fit well onto a 24-25 inch frame. Since womens proportions are somehwhat different, experimentation with frame sizes should be a consideration. Most experts recomend that women do not use an "open" style frame and do consider purchasing seats/saddles specifically designed for women.
b. Seat height: This varies on your height, the level of amputation and the type of shoes you wear!
As a general rule BK amps that have good strength in the residual limb should adjust seat height so that you can reach the ground with the toes of your good foot. If you do use your prosthetic side for stationary balance you need to adjust the height of the seat so that the majority of the foot is on the ground when sitting on the seat; this also applies to double bk's and symes. Since there is no flexion or dorsi flexion in your ankle(s) and a lampost or stop sign is not always convenient, you will need your seat slighty lower than if you used your non-prosthetic side for stationary balance.
Everyone must consider seat height as a major effect on your ability to ride and ride well. You should have 5-8 degrees of flexion in either limb at full extension. This can pose a problem for some AK prostheses. Some knee units that use a "dampening" effect to stop "clunking" at full extension whilst walking may cause the prosthetic limb to rise of the pedal as the limb approaches maximum extension whilst seated. Knee units such as CaTech and Mauch can be adjusted to give more of a free swing, generally the less resistancethe better when bike riding.
If the seat is too high either limb will feel like it being pulled down onto the pedal as full extension is reached. If the seat is too low both limbs will feel like they are not extending enough and may even hit you in the chest as you reach full extension.
Some bk and ak prosthetic limb designs involve various degrees of motion especially at full flexion. Knee units such as Mauch and CaTech do have a limited range and can actually can cause considerable damage to the knee unit if this range is surpassed. If you have what feels like the right seat height and your prosthesis does not seem to go through the full range of motion, it is time for a decison. Will a prosthetic adjustment for cycling detract from your walking? If cycling is your preferred method of transportation than it will be worth it. Get your prosthetist to make some minor adjustments, if you can take the bike with you and have your prosthetist look at the problem directly.
c. How to keep prosthetic limbs from falling off the pedals:
Probably the most difficult aspect of riding with a prosthesis especially for AK's. There are several methods of overcoming this problem.
i. Use of conventional methods: regular toe clips, straps or riding shoes are all possibilities for more serious riders. However before such devices are used several prosthetic issues have to be considered.
Foot Aligment toe in-toe out: Most prosthetic feet are set for walking, most are set slightly toe-out. However, this often proves detrimental for the amputee bike rider and bike pedals prefer feet to be set straight ahead with toes on the pedal. Toe clips and riding shoes will only allow the foot to attach to the pedal at the ball of the foot, this is not always conveneint, especially for short street riding.
ii. The use of a serrated metal pedal together with the serrated sole of a decent running shoe will give considerable traction for a prosthetic foot with limitations. Bumps and potholes will still cause the prosthetic foot to fall off the pedal, be forever vidulent in looking at the foot making sure it does not fall off the pedal. However, if you ever fall to your prosthetic side you have more of a chance of getting the prosthetic limb out and locked if an ak to stop you from a potentially nasty fall. Toe in and out is less of consideration using this method as you can place the foot at any point along the pedal.
Safety:
Is always a factor in any level of bike riding. A helmet(lid) is rapidly become law in many states and provinces in North America. A good pair of fingerless gloves with some heavy duty padding on the heel of the hand is your second most important safety device, especially when heavy duty moutain riding. Sunglasses are also an issue even if it isn't sunny. Sunglasses keep the rain, wind and the bugs out of your eyes, there's nothing worse than getting a wasp in your eye at 40 mph! I've even had rocks bounce off my sunglasses! Even a pair under $10 will do the job, the bigger style the better coverage of your eyes.
Safety is especially a factor when re-learning how to ride. Don't let your confidence hinge on a few mishaps at the beginning. The best surface to learn to ride of is short grass, preferably with a sligh decline slope. Check out you route beforehand, look for objects that are hidden and could cause you to either oversteer or lose you balance. Local parks with well cut grass are perfect for learning to ride.
Of course once you learn to ride, the next lesson is how to stop. Make sure you know the back brake from the font. Front breaks are far more effctive at stopping you and your bike than the back brakes. However, front breaks can often lead to your bike stopping with you continuing over the handlebars. Practce using the brakes in a stationary position, apply pressure to the back break first and then the front. Too much pressure will lock your wheels (especially on dirt) and they have not devised an anti-locking brake system for bikes yet.
For further reading on amputee bike riding from the prosthetists point of view check out the following article by Brian Mackie.
Book Recomendations:
The Bike Book by Haynes: Whilst Haynes have been producing top quality books for cars, their bike book is an excellent guide to the modern bicycle. Ranges from saftey, buying a new or used bike, setting them up and re-building all parts. The books page layout is excellent, lots of accurate photos (rather than handrawn sketches) and easy to follow, unpretencious instructions.
The Haynes Bike Book should be available at your local library or from any decent bike shop that sells books.
Also check out the following pages for amputee bike tips and safety:
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