RESUMEN
In this study a common yet very strenuous construction work activity, was evaluated biomechanically by studying electromyography (EMG) of the major neck muscles. The muscles studied were the sternocleidomastoid and the upper trapezius. Fifteen healthy participants (10 males and 5 females) with no history of musculoskeletal abnormalities participated in this study. The participants lifted 25%, 50%, and 75% of their maximum shoulder height static strength at neutral, maximally flexed, and maximally extended neck postures. The weight lifted as well as the neck posture significantly affected the activities of the neck muscles. Increase in the weight increased the activation of the neck muscles. The sternocleidomastoid muscle was most active at the extended neck posture, while the upper trapezius muscle was most active at the flexed neck posture. The results of this study indicate that the neck muscles play an active role during lifting and holding tasks at shoulder height. Thus, such tasks could be probable risk factors associated with neck disorders prevalent among construction workers.
Asunto(s)
Vértebras Cervicales/fisiopatología , Arquitectura y Construcción de Instituciones de Salud , Elevación/efectos adversos , Enfermedades Musculoesqueléticas/etiología , Cuello/fisiopatología , Enfermedades Profesionales/etiología , Adulto , Electromiografía , Femenino , Humanos , Masculino , Músculo Esquelético/fisiopatología , Enfermedades Musculoesqueléticas/fisiopatología , Enfermedades Profesionales/fisiopatología , Prevalencia , Factores de RiesgoRESUMEN
The purpose of usability engineering is to facilitate the deployment of new products by decreasing development costs and improving the quality of systems. This paper will discuss the development and delivery of a unique, theoretically based software tool that provides engineers and designers with easy access to the most recent advances in human-machine interface design. This research combines several theoretical views of the interaction process into a hybrid model. Based on this model, a software tool was produced that allows engineers to model the human interaction process within their design. The system then provides feedback on the interaction process through items such as: the amount of mental effort required by a user, the degree to which the system conforms to human capabilities, the expected time to complete the interaction, where potential human error may occur, as well as potential misunderstandings or points of confusion to the users. The designer may then use this information to improve the design of the system. Validation of this technique indicates that the hybrid model produces accurate predictions of usability attributes and that the technique transfers from the laboratory to the real world.