Design of a spring-integrated crutch for ascending stairs

Abstract

Using conventional underarm or forearm crutches is uncomfortable and awkward. Further, underarm crutches make climbing stairs difficult and unsafe. One may climb stairs with forearm crutches, which do not impede elbow movement, but doing so is fatiguing and requires upper body strength. In 2011, MIT Media Lab researcher Madalyn Berns demonstrated that incorporating into the crutch an elastic element that spans the elbow joint could reduce the metabolic cost of crutching up stairs. The elastic element stores energy when compressed by the biceps; the stored energy then aids the triceps in levering the user up the stairs. This thesis developed a safer, sleeker, and more comfortable spring-integrated crutch. The novel design uses a torsion spring to store energy during elbow flexion. The spring is compressed between a forearm cuff and an upper arm cuff. The design allows the patient to reduce metabolic cost by using upper arm muscles more effectively.