American Sign Language (ASL) interpreters are a vital resource both for people who are deaf and people who are hearing. Interpreters face a combination of high cognitive and high physical demands while interpreting, placing them at an increased risk for upper extremity musculoskeletal disorders and burnout. Research has shown that individual differences exist in signing style, causing some interpreters to have a less physically demanding signing style than others. Anecdotal evidence suggests that interpreters who start signing at a young age may have a decreased likelihood for developing upper extremity musculoskeletal disorders due to the possible acquisition of a technique that minimizes strain on the body. The objectives of this study were to analyze the impact that learning to sign at a young age has on wrist kinematics while signing, as well as how wrist biomechanics are affected by the type of signing task being completed, casual conversation or formal interpreting.

Three subject groups were studied in this research: eight interpreters who are early signers, eight interpreters who are late signers, and nine students who are deaf and use ASL. The students observed the lecture task completed by the interpreters and then all the subjects actively participated in the conversation task. Biomechanical variables for position, velocity and acceleration were measured in both the flexion/extension and radial/ulnar deviation planes. It was found that sign language acquisition history or learning to sign at a young age did not significantly affect wrist kinematics. The signing task, however, did have a significant effect on kinematic data for both interpreter groups. The interpreting task resulted in wrist velocity that was 5%-15% greater, on average, than the conversation task. This study shows that interpreting poses higher biomechanical demands than everyday signing, and that learning to sign later in life does not put a person at a greater risk for upper extremity musculoskeletal disorders.

Library of Congress Subject Headings

Interpreters for the deaf--Health; Sign language--Health aspects; Biomechanics; Overuse injuries

Publication Date


Document Type


Student Type


Degree Name

Industrial and Systems Engineering (MS)


Matthew Marshall

Advisor/Committee Member

Jacqueline Mozrall

Advisor/Committee Member

Marc Marschark


Physical copy available from RIT's Wallace Library at HV2402 .D665 2012


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