Comparison of user metabolic efficiency between traditional and spring assisted leveraged freedom chair models

Tests were performed to determine how the use of an elastic energy storage mechanism on the Leveraged Freedom Chair would affect the rider's metabolic efficiency. For this test, elastic bands were attached to the levers, and the rider's heart rate was recorded as he rode multiple lengths of a field in a timed trial, in both the spring assisted LFC and the traditional LFC. Efficiency in the spring assisted LFC, normalized by the efficiency measured on the traditional chair, was found to be [epsilon]n = .684. This may indicate that there is a higher metabolic cost associated with pulling than with pushing in the LFC. The lower efficiency may also have resulted from the arbitrary choice of spring constant, as well as viscoelastic losses in the elastic bands. The user experienced much higher fatigue in the traditional LFC, primarily in the latter half of the 887 meter course, suggesting that in spite of the current decreases in efficiency, the spring system could add value by allowing users the option to travel longer distances.

Department dc:contributor.department

Massachusetts Institute of Technology. Department of Mechanical Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2016

Author dc:creator

• James, Bassey Henry

Advisor dc:contributor.advisor

• Amos G. Winter, V.

• Mechanical Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/105702

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/105702