Monitoring of Sitting Postures With Sensor Networks in Controlled and Free-living Environments: Systematic Review

Abstract

Background A majority of employees in the industrial world spend most of their working time in a seated position. Monitoring sitting postures can provide insights into the underlying causes of occupational discomforts such as low back pain. Objective This study focuses on the technologies and algorithms used to classify sitting postures on a chair with respect to spine and limb movements. Methods A total of three electronic literature databases were surveyed to identify studies classifying sitting postures in adults. Quality appraisal was performed to extract critical details and assess biases in the shortlisted papers. Results A total of 14 papers were shortlisted from 952 papers obtained after a systematic search. The majority of the studies used pressure sensors to measure sitting postures, whereas neural networks were the most frequently used approaches for classification tasks in this context. Only 2 studies were performed in a free-living environment. Most studies presented ethical and methodological shortcomings. Moreover, the findings indicate that the strategic placement of sensors can lead to better performance and lower costs. Conclusions The included studies differed in various aspects of design and analysis. The majority of studies were rated as medium quality according to our assessment. Our study suggests that future work for posture classification can benefit from using inertial measurement unit sensors, since they make it possible to differentiate among spine movements and similar postures, considering transitional movements between postures, and using three-dimensional cameras to annotate the data for ground truth. Finally, comparing such studies is challenging, as there are no standard definitions of sitting postures that could be used for classification. In addition, this study identifies five basic sitting postures along with different combinations of limb and spine movements to help guide future research efforts.

Driver Position Measured Based on Textile Capacitive Sensor Array

“…This information has been commonly gathered by means of a Force-Sensitive resistor (FSR), although this sensor does not supply additional information such as the correct sitting posture during driving. Several works in the literature [1][2][3][4] present pressure sensors integrated into office chairs that could be used as a replacement for FSRs and also provide sitting posture information. However, these sensors are not fully integrated in textile seats.…”

Smart Office Chair for Working Conditions Optimization

“…It has been proven that back pain is more common between the ages of 25 to 45 years old, in both genders, thus affecting people in their peak of productivity [5]. Spinal disorders are the second leading cause of requests for medical leave from work and even the reason for early retirement; consequently, they create significant losses to the economy [5], [6]. For all these reasons, many experts believe that more attention should be given to this problem, which should be studied as a social disease.…”

“…The seated body posture has been classified in different ways by different authors [5], [6]. There are several clinical opinions on the categorization and classification of correct and incorrect postures.…”

“…There are three possible combinations to describe an ideal sitting posture: the first portrays the thoracic and lumbar regions as flat; the second describes a long lordosis, where both regions are lordotic; and the third combination corresponds to a short lordosis that almost imitates the standing posture, with thoracic kyphosis and lumbar lordosis [7], as depicted in Figure 1. However, even considering one of these ideal positions, if it is sustained for four or more hours, it can lead to pain and discomfort for the user; it is therefore important to take short breaks to relieve and relax the muscles [1], [5], [6], [7], [8]. Automated systems are one form of monitoring the user's position in a chair [9].…”