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.

National Institute of Health (NIH)
Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD)
Small Business Innovation Research Grants (SBIR) - Phase II (R44)
Project #
Application #
Study Section
Special Emphasis Panel (ZRG1-MOSS-F (15))
Program Officer
Shinowara, Nancy
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
Daedalus Wings, Inc.
San Francisco
United States
Zip Code