Canoe Seating System
Access to water-based outdoor recreation such as canoeing is difficult for individuals who have impaired sitting balance. The goal of this project is to design a modular universal canoe seating system to provide adequate support for a variety of users. This seating system will improve pelvic stability, trunk support and comfort for all paddlers. It will be designed to be suitable for use with commercial canoes used by rental, outfitting and instructional programs. The system will be adjustable and modular to accommodate a wide range of individuals. It will include a basic seating system with pelvis and low back support suitable for all users, and extended support(s) for users without independent sitting skills.
Need for a Canoe Seating System
Canoeing enhances access to outdoors and wilderness environments by providing transportation to areas that cannot be reached by land, or are inaccessible for people with mobility limitations. This group may include older adults, families with young children, and people with disabilities. Thirteen million canoes are rented or used in outfitting or instructional programs each year. Canoe rental facilities and instructional programs currently rely on commercially available seats. The paddlers using these seats must use balance and leg strength to maintain an effective sitting position.
Statement of the Problem
Standard canoe seats provide a bench for the paddlers to sit on or lean against. They do not stabilize the pelvis or provide lower back support. The functional benefits of pelvic stability are well documented for wheelchair users. Just as a wheelchair user needs a stable pelvis, the canoe user must maintain similar levels of stability to effectively paddle. Paddlers with no physical impairment can use leg, hip and trunk muscles to stabilize the pelvis and trunk. Although commercially available backrests are available, they are not designed to support individuals who are unable to sit independently. Such individuals must rely on an external back support system. Commercial canoe backrests do not provide lateral support for pelvic stability and have a minimal and often unstable attachment to the existing seat. In addition, commercially available seats usually do not provide padding sufficient to prevent pressure ulcers or abrasions, and are usually not compatible with the use of a personal cushion or seating system.
Design of Concept Prototype
A concept prototype for a modular canoe seating system has been designed. The concept system is modular to provide different amounts and locations of support. The concept system consists of: 1) basic seating module with adjustable pelvic supports, 2) backrest extension with adjustable backrest upholstery, and 3) lateral trunk supports.
The proof of concept device was constructed of materials similar to those used in current lightweight wheelchair construction. The seat was then mounted on the fore and aft bench seats in two different canoes commonly used by canoe rental outfitters.
Evaluation of Prototype
The prototype system was evaluated on land by three seating experts and three others to obtain subjective feedback on the comfort and support provided. In addition, the device was tested on a river by two experienced paddlers with spinal cord injuries. The evaluators reported perceived benefits of increased comfort, increased pelvic support, increased low back support, greater seat cushion comfort, better stability when leaning, and increased paddling efficiency. Areas identified as needing additional development include an adjustment for height of the back support, a method of leg stabilization, easy adjustment of lateral pelvic supports and a slightly shorter seat depth.
The prototype is capable of providing improved pelvic and low back support, stability and comfort for users with and without disabilities.
Phase I Work
The initial feedback from evaluators indicates that the prototype canoe seat is effective in providing improvements to pelvic and trunk stability and increasing comfort. More research is needed to incorporate suggested improvements and features. Areas that will require further development include the strength and durability of the materials used to fabricate the device and safety for the system user.
Several evaluators requested additional hardware to stabilize the lower extremities. Development of this hardware could significantly improve lower extremity and pelvic stability but will also create additional problems for ingress and egress.
Universal Paddling Seat:
This work is funded by the National Center for Medical Rehabilitation Research in the National Institute of Child Health and Human Develop-ment at the National Institutes of Health through Small Business Innovation Research Phase I Grant #1 R43 HD36944-01A1.
Adaptive Water Sports Equipment
Many people with mobility limitations have been unable to participate in water sports such as surfing due to a lack of recreation technologies that can accommodate their needs. A new technology developed for surfing has been adapted for people with mobility limitations. Those with lower extremity limitations and good arm strength can now surf and kayak with a fiberglass wave ski.
Developing a Prototype
As a student project advisor, Peter Axelson worked with Alex Dinello of the University of Virginia to develop the first adaptive wave ski prototype. With the help of wave ski designer Merv Larson, they created a slightly longer and wider model that would provide additional stability. A custom-molded orthotic seating system inserted into the wave ski deck allows a user to sit in the board and eliminates the need to cling to its surface. A padded aluminum knee support with a quick release Velcro strap secures the rider\'s legs aboard the ski. A four-point strap harness supports the rider\'s torso and attaches to the ski using a single release mechanism. The rider uses a kayak paddle to propel, steer, and balance the lightweight craft.
The adaptive wave ski prototype is being evaluated for safety and performance.
This was a student project sponsored and funded by the University of Virginia Rehabilitation Engineering Center, and Alex Dinello, a graduate of the University of Virginia Engineering program and student intern at Beneficial Designs, Inc.
Need for a Pulling Exercise Apparatus
Exercise machines provide the opportunity to strengthen specific muscle groups. Wheelchair riders in particular tend to overdevelop the muscles used to make transfers and propel a wheelchair. Strengthening the "pulling" muscles that oppose normal wheelchair propulsion improves shoulder stability, increases functional efficiency of everyday activities, and reduces the likelihood of overuse injuries.
Dynamic Rowing Machine Design
A dynamic rowing machine was developed to exercise the "pulling" muscles that oppose normal wheelchair propulsion. The rowing machine features a cantilevered seating system similar to that of a mono-ski. A bicycle ergometer with weighted fly wheel provides resistance. The user holds two hand grips connected to the fly wheel with pulley cords and reaches as far forward as possible. Sitting up and pulling the hand grips toward and as far past the body as possible strengthens the pulling muscles over the full range of motion. Returning the hands to the fully forward position retracts the pulley cords and allows the process to be repeated.
Developing a Prototype
A preliminary prototype machine proved feasible to build and effective at strengthening targeted muscle groups. Beneficial Designs seeks support to modify the design so that it can be used with commercially available rowing ergometers. Design students at Montana State University created a next-generation device that uses add-on technology that is compatible with standard Concept II ergometers.
This was a student project at Montana State University and was funded by Concept II Ergometers and Beneficial Designs, Inc.