SBIR-STTR Award

An innovative lever propulsion attachment for pushrim wheelchairs has been developed. This design promotes a natural and efficient propulsion motion which can eliminate injuries of the shoulders, elbows, and wrists experienced by the majority of the 1.4 million pushrim wheelchair users in the United States. It can also be utilized by more functional electric wheelchair users, enabling them to avoid the health problems associated with a sedentary lifestyle. The design utilizes a single lever in front of the user's knees to drive the front wheel. Steering and braking is by a standard bicycle interface, with the entire drive unit rotated for steering in much the same manner as handcycle propulsion attachments. The advantages of lever propulsion over handcycle propulsion are that less range of motion is required of the shoulder, arm, and wrist, and the user can utilize the part of the propulsion stroke appropriate for their disability. The proposed design is also considerably more lightweight, compact, and maneuverable than handcycle designs. The advantages of attachment designs over dedicated design are that effective use can be made of existing pushrim wheelchairs and users can revert to pushrim functionality when appropriate. In Phase I the propulsion mechanism, the most innovative and critical part of the design, will be tested according to clear functionality and robustness criteria. The stability of the design will also be verified. Phase II will include the development of the gear change, braking, and suspension systems, the attachment to pushrim wheelchairs, and comprehensive user testing.

Thesaurus Terms:
assistive device /technology, biomedical equipment development, clinical biomedical equipment biomechanics, ergonomics, injury prevention, repetitive motion injury

A simple innovative lever propulsion attachment for pushrim wheelchairs will be developed that can bring the advantages of lever propulsion to wheelchair users. The majority of 1.4 million manual wheelchair users in the United States suffer from Repetitive Strain Injuries (RSI) of the shoulders, elbows, and wrists due to the awkward biomechanics of pushrim propulsion. These injuries force users to transition prematurely into power wheelchairs. Disadvantages of power wheelchair use include high cost, reduced transportability, and, most importantly, the loss of therapeutic physical exertion. The health problems of a sedentary lifestyle result. Independent studies have consistently shown that lever propulsion is significantly more efficient than manual pushrim propulsion and avoids the injury mechanisms that result in RSI. However, no lever design has had significant success in the market because they do not have all the features and capabilities required by users. The proposed design utilizes a single lever in front of the user's knees to drive a wheel directly in front of the user's feet. Steering and braking is by a modified bicycle-style interface, with the entire drive unit including the lever and handlebar rotating for steering similar to handcycle attachments for wheelchairs. The device attaches and detaches easily to virtually any wheelchair. The single lever design and interface design will be especially useful for users with limited strength and dexterity. Users with a left/right imbalance, such as stroke survivors, can utilize this design in the rehabilitation of their weaker side. The attachment is fully adjustable to most users. In Phase I, maneuverability, gear change, stability, traction, reliability, weight, cost, and attachment feasibility were successfully demonstrated. Phase II will include the implementation of a gear shifting and forward-reverse shifting system. The steering, drive, control, and attachment systems will be refined. There will also be comprehensive industry standard International Standards Organization (ISO) testing to certify the reliability and safety of the design. Finally, thorough user testing will be performed to verify functionality compared to manual wheelchairs. The simple, inexpensive, and innovative design in combination with the use of existing components, materials, and fabrication techniques will combine to create an entirely new product category. The company also has experience commercializing innovative mobility products. With a strong market position the lever attachment is poised to capture a significant market share of the $800 million dollar wheelchair market. Introduction of this innovative product in the market will stimulate further technical innovation in an industry constrained by antiquated structural and technological paradigms.

Public Health Relevance:
PROJECT NARRATIVE Most of the 1.4 million manual wheelchair users in this country will suffer from Repetitive Strain Injuries (RSI) due to the awkward and inefficient biomechanics of propulsion. Independent studies have consistently shown that the natural and efficient biomechanics of lever propulsion avoids these injury mechanisms. The proposed revolutionary lever drive attachment for manual wheelchairs would be the first practical and affordable product that meets all the maneuverability and functional requirements as defined by users.

Public Health Relevance Statement:
PROJECT NARRATIVE Most of the 1.4 million manual wheelchair users in this country will suffer from Repetitive Strain Injuries (RSI) due to the awkward and inefficient biomechanics of propulsion. Independent studies have consistently shown that the natural and efficient biomechanics of lever propulsion avoids these injury mechanisms. The proposed revolutionary lever drive attachment for manual wheelchairs would be the first practical and affordable product that meets all the maneuverability and functional requirements as defined by users.

Project Terms:
Apoplexy; Automobile Driving; Beavers; Bicycling; Biomechanics; Castor; Castor Beaver; Categories; Cerebral Stroke; Cerebrovascular Apoplexy; Cerebrovascular Stroke; Cerebrovascular accident; Country; Cumulative Trauma Disorders; Devices; Disadvantaged; Drivings, Automobile; Elbow; Electric wheelchair; Ensure; Exertion; Foot; Goals; Health; Industry; Injury; International; Knee; Left; Leg; Life; Life Style; Lifestyle; Manual wheelchair; Manuals; Marketing; Methods and Techniques; Methods, Other; Nonpowered Wheelchairs; Overuse Injury; Overuse Syndrome; Pes; Phase; Physiatric Procedure; Physical Health Services / Rehabilitation; Physical Medicine Procedure; Physical Therapeutics; Physical Therapy Procedure; Physical Therapy Techniques; Physical therapy; Physiotherapy; Physiotherapy (Techniques); Physiotherapy Procedure; Position; Positioning Attribute; Power stroke; Powered wheelchair; Rehabilitation; Rehabilitation therapy; Rehabilitation, Medical; Repetition Strain Injury; Repetitive Motion Disorders; Repetitive Strain Injury; Repetitive stress injury; Safety; Shapes; Shoulder; Side; Stroke; Survivors; System; System, LOINC Axis 4; Techniques; Testing; Time; Traction; United States; Vascular Accident, Brain; Weight; Wheel Chairs; Wheelchairs; Wheelchairs, Mechanical; Wing; Wrist; brain attack; cerebral vascular accident; cost; design; designing; driving; experience; foot; innovate; innovation; innovative; meetings; mobile assistance device; mobile assistance system; mobile assistive device; mobile assistive system; product development; prototype; public health relevance; rehabilitative; repetitive motion injury; sedentary; stroke; success