Comparison of FitBit® Ultra to ActiGraph™ GT1M for Assessment of Physical Activity in Young Adults During Treadmill Walking

Introduction: Accelerometers are used to quantify energy expenditure in field research. The ActiGraph GT1M (ActiGraph) is a commonly used accelerometer for research. The FitBit Ultra (FitBit ) is a low-cost alternative to the ActiGraph; however, there is limited research on the validity of this device.