Accelerometer-based systems and methods and quantifying steps

A method of counting steps from outputs of a first accelerometer and outputs of a second accelerometer, the first accelerometer measuring linear acceleration at least along an anterior-posterior axis of an individual, the first accelerometer and the second accelerometer coupled to an individual and in communication with a processor, the processor in communication with a non-transitory computer readable medium, the non-transitory computer readable medium storing instructions for execution by the processor to execute the steps of the method, the method comprising:

• determining a plurality of time periods, each of the plurality of time periods being a time period;
• determining readings using the outputs of the first accelerometer and the outputs of the second accelerometer the outputs of the first accelerometer and the outputs of the second accelerometer being generated at least every one third of a second;
• identifying counted peak heights, each of the counted peak heights comprising a maximum reading during a time period in which the maximum reading is greater than a rest threshold, the rest threshold determined by:
• receiving readings from the first accelerometer and the second accelerometer during a period of rest,
• identifying a rest maximum, the rest maximum comprising a greatest reading generated by the first accelerometer or the second accelerometer during the period of rest, and
• determining the rest threshold using the rest maximum;
• determining a peak threshold for each of the plurality of time periods having a counted peak height, the peak threshold comprising a first weighted average of two or more counted peak heights;
• identifying counted amplitudes, each of the counted amplitudes comprising a difference between the maximum reading and a minimum reading during a time period in which the counted peak height exceeds the peak threshold;
• determining an amplitude threshold for each of the plurality of time periods having a counted amplitude, the amplitude threshold comprising a second weighted average of two or more counted amplitudes;
• and
• incrementing a counter if the counted amplitude exceeds the amplitude threshold associated with the time period in which the counted amplitude occurred, a number stored by the counter representing a number of steps taken by the individual.