Monitoring floor vibrations to evaluate objectively physical activity during housework activities

The self-monitoring of physical activity (PA) is an effective supporting strategy for the adoption of active lifestyles. However, accurate predictions of the PA remain challenging in certain situations. In the present study, we developed a smart-home floor-vibration monitoring system able to quantify PA during housework activities. Ten subjects performed four different activities (sitting, ironing, cooking, and cleaning) in the Ocha-House, an independent experimental house with accelerometers installed on the floor. The floor vibrations were monitored and the PA was evaluated objectively using two Actigraph GT9X activity trackers (worn on the waist and the wrist, respectively). A data processing algorithm was designed to process the floor-vibration data, estimate the number of steps, and predict the volume of physical activity performed in the house. A good correlation was found between the quantity of floor vibrations measured by the Ocha-House and the objective evaluations of PA made by the waist-worn monitor (r=0.9, p<0.00l). Compared to the two GT9X monitors, the floor vibration system was also able to produce more accurate predictions of the number of steps. The Ocha-House floor-vibration monitoring system was able to perform quantitative assessments of PA for four different housework activities. We believe that floor vibration-based smart-home systems can provide relevant pieces of information for the objective evaluation of PA when people are staying at home.