Semester

Spring

Date of Graduation

2011

Document Type

Thesis

Degree Type

MS

College

Statler College of Engineering and Mineral Resources

Department

Industrial and Managements Systems Engineering

Committee Chair

Ashish D. Nimbarte.

Abstract

In spite of strong prevalence of neck and shoulder musculoskeletal disorders among health care workers, the effect of their routine work activities, which demands physical exertion and high cognitive load, on the loading of neck-shoulder musculatures is not clearly understood. Additionally, it is currently unknown as to how the internal loading of the neck-shoulder musculature caused by the external work-related factors is affected by the individual personality. The purpose of this study was to evaluate the musculoskeletal loading of neck-shoulder musculature when human participants performed physically and cognitively demanding exertions. The loading of neck-shoulder musculature was evaluated using objective and subjective assessment methods. Electromyography (EMG) of the neck-shoulder musculature was used as the objective assessment method, whereas NASA-TLX scores were used as the subjective assessment method. Individual personality types were determined using MBIT personality test. Twenty (18 males and 2 females) participants were recruited for data collection. Each participant performed two experimental sessions: Session 1 - physical exertion, participant performed 10 maximum static pulling exertions in semi standing posture simulating a bed-to-stretcher patient transfer task. Session 2 - physical and cognitive exertion, during this session, in addition to 10 static pulling exertions (same as session 1), the participant performed mentally demanding tasks such as memorizing and recalling a list of words. The activities of three major neck-shoulder muscles: upper trapezius, sternocleidomastoid, and cervical trapezius, were studied. Muscle activity data showed that the neck-shoulder muscles worked harder while performing a combination of physical and cognitive exertions than purely physical exertions. The effect of the loading of neck-shoulder muscles was found sensitive to the individual personality. In general for all the muscles, among the participants with feeling personalities, a higher increase in the activation level of muscles was observed. The knowledge gained from this study imply that investigations viewing the entire work system (the interaction of physical and psychosocial workplace issues, as well as individual factors) will most likely to derive the root causes of neck-shoulder MSDs among healthcare occupations.

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