We have recently validated a new device for measurement of physical activity and found it to detect type, duration and intensity of many types of physical activity at better than 98% accuracy. After further validating this device to determine if it can also accurately assess energy expenditure, we will use it to collect cross-sectional data on free-living physical activity and energy expenditure in adolescent girls.

Study3: healthy lean and obese adults, at least 18 years of age.