Exercise Effect of a Chair with a Forward-Declined Seat and a Footrest

Abstract

People sit on chairs for long periods of time each day and hence it would be convenient for them if they could exercise while sitting. This paper proposes a chair with a forward-declined seat and a footrest for allowing the user to exercise while sitting. When sitting on the chair, the user has to apply forces through his/her legs and feet to prevent slipping down from the seat. In the experiment, first, the required moment on each body joint was calculated using a digital mannequin positioned on a 3D-model of the proposed chair, and the active muscles were identified. Next, electromyography (EMG) of the identified muscles was performed in sitting on the proposed chair and other types of chairs. After the EMG measurements, the subjects provided their subjective impressions on topics such as the ease of sitting on the chair for a long time. Finally, after comparing the results from the EMG and subjective impressions, it was confirmed that a user of the proposed chair was able to exercise while sitting on it.