Acceleration sensors measure sitting activity on dynamic office chairs
Author: Daniel Baumgartner, Prof. in Biomechanics ZHAW, Zurich University of Applied Sciences
rotavis AG, a start-up company based in Winterthur, has developed a new type of technology together with biomechanics experts from the Zurich University of Applied Sciences (ZHAW) that promotes active sitting.
The mobile seat surface activates the movements of the pelvis and spine in a similar way to the salsa swing, thus stimulating the muscular system in the back. The increased mobility is conducive to activating the musculoskeletal system of the spine and intervertebral discs.
Test method
In order to develop a physiological dynamic adapted to the body, the first step was to measure 57 test subjects in the movement analysis laboratory of the ZHAW Department of Health. The researchers analyzed the natural movement of the spine in order to reproduce it on the new chair.
This was followed by a user study with a total of 30 test subjects in collaboration with a major local insurance company in Winterthur. The 30 prototype chairs were equipped with MSR145 mini data loggers on the mobile seat to detect the movement patterns during the active sitting time.
Data loggers used
The MSR145 mini data loggers used in the study recorded the movements in all three axes at a measurement rate of 10 Hz for two weeks without interruption using a 3-axis acceleration sensor (±15 g). The data loggers were equipped with a slot for a microSD card to ensure a storage capacity of one billion measured values. The logger manufacturer MSR provides setup, reader, viewer and online software for configuring the data loggers and evaluating the data.
Measurement results
For an average working day in a seated position, the seat that moves to the side was activated. Doubling the active sitting time on the chair resulted in a significant increase in the intensity of movement in the back. The goal of increasing activity was thus clearly demonstrated. A further study is planned, which will also demonstrate the reduction in pain with the new dynamic office chair.