A wrist-worn device monitors movements of a user. A sensor assembly of the wrist-worn device is configured to detect movement of the user and generate sensor data based on the movement detected. A controller connected to the sensor assembly obtains movement data based on the sensor data. An antenna connected to the controller is configured to operate at a desired frequency when a wrist of the user is received by the device such that the movement data is wirelessly transmittable from the wrist-worn device to an electronic device. The antenna may exhibit a different design and configuration depending on the size of the wrist-worn device.