Wearable Sensor Technology Helps Measure Physical Activity

A new wearable sensor network could help assess a person's physical activity and overall well-being.

Researchers from Michigan State University (MSU; East Lansing, USA) developed the wearable technology that is based on three small wireless sensors worn on the wrist, upper arm, and lower leg; during any physical activity, the sensors will measure not only the frequency, intensity, and time, but also the type of activity. The data then will be wirelessly transmitted to medical service providers' servers for remote assessment and well-being management. A working prototype has been built, and testing is scheduled to begin on graduate students in the MSU department of kinesiology. The results of the pilot study will allow the researchers to begin developing advanced features, such as on-body statistical data processing and real-time feedback to participants.

Currently, studies that measure physical activity are based on the use of accelerometers--wearable devices used to measure kinetic motion. But while an accelerometry-based approach can be used for differentiating postures such as walking and running, it is not very effective for identifying and differentiating between low-activity postures such as sitting and standing, as well as an inherent inability to measure uphill movement and activities done while standing still, among others.

"If we cannot accurately measure physical activity, we cannot know what is effective and what is not in battling obesity and other health risk factors," said Professor Karin Pfeiffer, Ph.D., of MSU's department of kinesiology. "By detecting more information about physical activity, we can begin tailoring effective exercise programs. This will help us immensely as we try to reverse some of the alarming trends seen in childhood health."

"With the traditional accelerometry-based approach, we monitored activity only by measuring the individual body part movements, not by their distance to each other," added Subir Biswas, Ph.D., a professor of electrical engineering. "With this technology, we can now measure acceleration, tilt, posture, the proximity of limbs to each other, all in collaboration with each other."

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