Recent interest in wearable activity-tracking devices such as pedometers and accelerometers is “an exciting trend,” says UMass Amherst kinesiology professor and chair Dr. Catrine Tudor-Locke, but because each commercial device uses its own proprietary outputs, researchers lack a standard measure when interpreting activity levels across devices.
Now, she has received a grant, expected to total $2.2 million over five years, from NIH’s National Institute on Aging to develop a common metric that can be collected and interpreted across the variety of pedometers, accelerometers and other wearable trackers now in use for personal activity level monitoring. At present, the commercial aspect of accelerometry “remains a lamentable source of frustration to those who yearn for standard measures,” she says.
Dr. Tudor-Locke says researchers need to establish an accurate and reliable measure of the relationship between ambulatory cadence, or steps per minute, and intensity, or metabolic rate, no matter what device is used. This research will provide clear and simple guidance for the cadence associated with a given intensity. For example, 100 steps per minute might be considered moderate intensity, while 130 steps would be vigorous.
She notes, “A common metric that could be collected and interpreted across objective instruments, including those used in the lab and in the real world, would be very valuable. The ability to confidently interpret common cutpoints across instruments would be ideal.”
No similar data exist at this time, Dr. Tudor-Locke notes. Her study will calibrate cadence and intensity in 260 adults, groups of 10 men and 10 women in each five-year age category, between 21 and 85. Using cadence, a direct, minimally processed reflection of locomotor quality, is an intelligent innovation because it is reasonably translatable across multiple devices as shown in pilot studies, the kinesiologist says.
Further, Dr. Tudor-Locke is very interested in making sure this information, once established and verified, will be simple and suitable for use in easy-to-understand messages about healthy activity levels for each age group. This project will thus lay the foundation for establishing cadence as the preferred spatial-temporal parameter of gait for both research and public health purposes.
A secondary aim will be to compare different instruments’ abilities to accurately detect cadence at different speeds, to give the investigators confidence in comparing this metric among different instruments. To achieve this, they will collect cadence using multiple commercial and research grade devices and oxygen uptake data during a treadmill assessment of incrementally faster paces. They will also collect these data during mock common activities such as vacuuming, watching television, folding laundry, walking up and down stairs and taking a walk.
Dr. Tudor-Locke, the recognized expert on “how many steps are enough?” says 10,000 per day is “a laudable number” to strive for, but another way to state the goal is 30 minutes per day or 150 minutes a week of moderate activity. “However, just getting off the couch and starting to move gives you immediate benefits, and every time you increase even a bit more, you get additional health benefits,” she adds.
The researcher says the average American adult takes 5,900 to 6,900 steps per day, “and we’re trying to get that higher.”