The effects of speed and force of keyboard operation on neck-shoulder muscle activities in symptomatic and asymptomatic office workers

The study demonstrated different reactions of symptomatic and asymptomatic office workers when they were subjected to the same physical stressors. These inter-individual differences in physiological and psychological responses should be considered when ergonomic interventions are introduced. The results also demonstrated that the factors of speed and force of keyboard operation may have important influences on the muscle activities and discomforts in computer users.