Why Fibion is the most accurate sensors to measure energy expenditure of daily activities?
This blog post explains what technological differences in the Fibion device provide it considerably better starting point for accurate energy expenditure estimation than other devices on the market (be it consumer or research device). Moreover, we show the same in numbers based on a validation study.
Due to scientific rules related to publishing, we cannot present here (yet) the latest full results of the validation study, as the study is not yet published officially. But if you want to see them, send us an email at firstname.lastname@example.org and we are glad to provide that information. Results shown below are based on a university study which was the basis for the white paper of Fibion and used discrete task performed on a treadmill and cycle ergometer.
The energy expenditure estimate of Fibion is based on three things: the position of the device, the movement of the device, and the background information of the participant. For example, when the algorithms inside the device know that the wearer is standing, a pre-determined equation for the standing energy expenditure is used. This is possible because Fibion can very accurately detect different physical activity types like explained here. Because standing of a heavy person burns more energy than standing of a light person, the device uses this information to adjust the output on the background information of the wearer.
Further, the algorithm takes into account the amount and movement speed of the leg (device), which in human locomotion are linked to energy expenditure. For example, during light walking the legs are moving considerably slower than in the running and device can accurately, therefore, detect the difference in energy expenditure between walking and running.
The energy expenditure estimates have been developed in laboratory conditions, where the posture and movement signal of the device were compared against truly measured energy expenditure (with a method called indirect calorimetry). In addition, the background information of the participants were used to develop regression equations for each activity type separately, which are used to give an accurate output for energy expenditure.
How accurate is Fibion in measuring energy expenditure?
The energy expenditure output of the Fibion Device has been validated in laboratory studies against indirect calorimetry, which is the most accurate method to measure physical activity energy expenditure. Healthy adults performed three walking activities (2, 4 and 6 km/h) and three running activities (8, 11 and 14 km/h) on a treadmill and three cycling activities (50W at 40 rpm, 125W at 60 rpm and 200W at 80 rpm) on a stationary bike. Physical activity energy expenditure was measured by indirect calorimetry and the Fibion Device, and these energy expenditures were compared to find out how accurately Fibion measures energy expenditure against indirect calorimetry.
Based on these results, the energy expenditure estimate of the Fibion Device is largely in accordance with indirect calorimetry. During higher running speeds and during heavy cycling Fibion slightly underestimates physical activity energy expenditure, but during walking and normal cycling the energy expenditure output is very accurate. Importantly, Fibion is very accurate in measuring energy expenditure of normal daily life physical activities, like slow walking.
The purpose of the second study was to compare the energy expenditure output of Fibion into that of heart rate sensor and Actigraph GTX3+ accelerometer, which are the most widely used devices to estimate energy expenditure in large-scale scientific research studies. Healthy adults performed the same protocol as in the study 1 while wearing the three devices: Fibion on thigh, Actigraph GTX3+ on waist and heart rate sensor on chest. The energy expenditure output of the sensors was compared to find out their accuracy.
Based on the results, the Fibion Device measures energy expenditure of walking, running and cycling more accurately than Actigraph GTX3+ device, when using heart rate as a reference method. Although both accelerometers underestimated running energy expenditure, the underestimate of Actigraph GTX3+ was bigger than that of Fibion. Importantly, Actigraph GTX3+ estimated cycling energy expenditure being extremely low, almost on resting level. The main reason for the observed differences might be the sensor placement. Fibion, located on the thigh, is more sensitive to different activities as compared to Actigraph GTX3+, which is located on the waist. In addition, Fibion is capable of recognizing different activities, which makes energy expenditure estimate more accurate.
What to say to your customer?
Many health and fitness professional are using Fibion for their consulting work to achieve better results with their customers. Following paragraph can be used as a summary to explain to interested customer how Fibion can provide accurate energy expenditure and possibly why results differ to other devices the customer have used previously:
“Fibion Devices measures your activity and energy expenditure based on three things: the position of the Fibion Device, the movement of the Device, and your background information. For example, when you are sitting, the device is laying on your thigh and moving very little. During standing the device turns vertically along with your thigh. During walking the Device is moving while you walk, and during running the movement is more intensive. This is why it is very important to wear the device on the front side of the thigh. The third thing, which helps in energy expenditure estimation, is your background information. For example, the more you weight, the more energy you burn during walking because you have more weight to carry.”
Measuring energy expenditure accurately is important, for example, to estimate what amount and types of physical activities consume enough energy for weight loss. With this information it is easier for an individual to create daily routines that fit their schedule and lifestyle and effectively help in the weight loss.