KidWalk Bicycle Attachment (Loyola Marymount University)

Timothy Burdiak, Nolan Smith, Nick Polito, Ali Abdulaziz



A bicycle attachment was created for Prime Engineering’s KidWalk 2 Mobility System to offer another means of fitness, gain coordination, and obtain a source of freedom to current owners. The project was inspired by the client, a 5th grader who has Dystonia which is a neurological disorder that hinders his ability to walk on his own. Children who are confined to a wheel chair while maturing are unable to develop proper muscle movement in their legs, arms and bodies. This confinement sometimes leads to extreme surgeries and intense physical therapy later in life. A bike prototype has been constructed and tested for safety and ease of use to help solve this issue.


The child, for whom the team designed the bicycle attachment, goes through vigorous and expensive training to improve his motor functions. The goal was to make an affordable and effective bicycle attachment that his parents or guardian can easily connect to his existing KidWalk 2 Mobility System. Exercise is important for children who cannot walk on their own because of two main reasons. The first reason being that when growing children cannot walk on their own their Achilles tendon shortens. Once the child may be ready to try walking in his or her future, they must go through an expensive surgery to lengthen their Achilles tendon. This procedure is not covered by insurance, which makes it very expensive. Secondly, the child’s digestive system starts to fail, leading to loose bowels and other complications, which are preventable by exercise (1).

With the aid of the bicycle attachment, users will be able to stay active and have a longer range when commuting around town. Bicycling targets the legs, the core muscles and improves arm strength. Current bicycles on the market range in the thousands of dollars, and are single function devices. With the bicycle attachment, parents or guardians will be able to purchase it for much less ($500 target price). According to an article submitted to the official journal of RESNA, Disparities in Usage of Assistive Technology Among People with Disabilities, children with neurological disorders are amongst the “… least likely to use any assistive technology” (2). It is believed that, with this low cost bicycle attachment, children and parents will combat the health problems caused by the sedentary lifestyle associated with neurological disorders, and promote the usage of assistive technologies worldwide.


To offer the client another means of physical exercise which will help him to strengthen and gain coordination in his legs and to offer him the chance to enjoy riding a bicycle.


In order to create a bicycle that attached to the walker, several factors needed to be addressed. The bicycle needed to be lightweight, attach to the walker easily, support a mid-sized child, turn easily, and be able to stop. The bicycle consisted of three major components: The steering system, the drive system, and the attachment configuration to the walker.


The frame was conceived out of multiple iterations. It started as a rather bulky design, and then changed to a more sleek traditional style bicycle. It is constructed out of Aluminum 6061-T6 square tubing. The reason for this was ease of fabrication; future models will be made out of circular tubing to achieve a more traditional bicycle aesthetic.


Figure 1: Bicycle Attachment and KidWalk Assembled


Since the client is in an upright position in the KidWalk, a taller “chopper” style fork was used to allow the handlebars to reach his hands. This way the walker could be steered easily and comfortably. Attached to the fork arms are two rubber tie downs that keep the steering assembly at a neutral position if the handlebars are released. This keeps it safe and effective if the user is too weak to return the steering apparatus back to its original position or loses control.

Figure 2: Steering Assist System

Drive System

The drive system was taken from a 12” kid’s bike. This made it easier on the team, because it is not easy to order such small bicycle parts. The crank set, rear wheel, seat, seat collar, handlebars and front wheel were all used from the kid’s bike. A new chain was measured and installed because the bicycle attachment is much larger than the kid’s bike. The benefits of using a kid’s bike are small sized parts that fit the client more comfortably and a small crank set allowing the bike to be easier to pedal.

Figure 3: The Client Using the Bicycle Attachment

System Attachments

Attaching the bicycle to the Kidwalk needed to be quick and simple. Undergoing many iterations including multiple pin assemblies and difficult welding were considered, the team concluded on designing the rear clamp in a trailer hitch fashion. The end of the bike frame would insert into a female end that is attached to the walker while two more clamps that come out of the side of the frame attach to the walker as well. This gives the bicycle three points of contact to the walker constraining it from moving side to side or up and down freely. To prevent lost parts from occurring, the parts of the clamps are all either attached to the KidWalk at all times or are attached via lanyards to the bicycle frame at all times.

Figure 4: Rear Clamp

Figure 5: Side Clamp

Figure 6: Side and Rear Clamps in Use


Using physical testing for usability and ease of use with the client, the results proved that the bicycle attachment worked and was able to be controlled in a safe and reasonable fashion. Although he had never ridden a bicycle within a half hour the client was able to power it. There is a definite learning curve that needs to be overcome, but he made excellent progress in just one day. Some assistance was needed to steer, however. The attachment pieces functioned properly and the entire assembly of the walker and can be fully secured in as little as 45 seconds, and weighs 25 lbs.

The turning mechanism was somewhat difficult for him to use, however it did keep its true course and did not veer off to any particular direction. This too will be a new thing for him to learn.

The attachment system held on tightly so that no unnecessary movement or vibration in any direction occurred.

The following is a quote from the client’s mother after the first trial of the prototype.

“Seeing neighborhood children freely exploring their world on their bicycles was always bittersweet. We had tried a few adaptive tricycles when my son was young but he never took to them, and although he’s able to use his walker, long distances present a challenge. Now that he has a specially adapted bicycle designed around the walker he already uses, it’s truly a wish come true!”

– Client’s mother


The team hopes to see this bicycle design become commercially available as an attachment for all owners of a KidWalk. The bicycle will be continued to be designed as a more functional and aesthetic bicycle.

After initial tests with the bicycle attachment and the client, the system proved to be safe and effective at accomplishing the projects goals. The client will need further training on the bicycle, being he has never ridden one before. The coaster breaks did their job, and stopped him immediately when he pedaled backwards. The steering system worked great in straightening the bike to go forward without the client having to hold the handlebars. After showing the client’s mother, how to attach and detach the bike, she could do it on her own with relative ease.


Special thanks to our client and his parents for being so helpful and creative. To Bruce and Mary Boegel of Prime Engineering for providing their extensive knowledge in the assistive technology field, also for their sponsorship and support. To Dr. Matthew Siniawski of Loyola Marymount University for providing us insight and advice. Lastly to John McLennan for contributing his expertise in metal machining at the Loyola Marymount machine shop as well as Komax Systems for the use of their machine shop.


1. Dunn, R. B., Walter, J. S., Lucero, Y., Weaver, F., Langbein, E., Fehr, L., Johnson, P., & Riedy, L. (1998). Follow-up assessment of standing mobility device users. Assist Technol, 10(2), 84-93. Survey study assessing the perceived benefits of standing devices used by patients with Spinal Cord Injury. Level IV.

2. H. Stephen Kaye PhD a , Patricia Yeager MS b & Myisha Reed BA b a Institute for Health & Aging, University of California, San Francisco, California b California Foundation for Independent Living Centers, Sacramento, California Version of record first published: 22 Oct 2010.


Timothy Burdiak

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