way the user can initiate the posture monitoring mode of the device 210 without having to release his or her golf club in one embodiment the sequence of user movements includes at least two steps performed in a specified order in which each step requires the user to look in a specified direction the device 210 may provide audible visible and or tactile confirmation of the proper execution of the ordered steps the sequence of user movements is designed to assure that the user is unlikely to perform the movements unintentionally for example after performing the calibration method of fig7 a user engaged in a round of golf may initiate the posture monitoring mode of the device 210 by performing a specified sequence of movements which based on the resulting orientations of the device 210 relative to the user effectively causes the apparent gravity vector g to retrace the path from a direction corresponding to the vector g 2 620 see fig6 to a direction corresponding to the vector g 1 610 see fig6 and back to the direction corresponding to the vector g 2 620 in a golfing application the specified and corresponding sequence of user movements may include addressing the golf ball looking at the horizon and addressing the golf ball again.