The accelerometer technology has been around since the early 1920’s, however the mechanism of the technology has remained fairly similar over the years. The earliest accelerometer was developed by McCollum and Peters in 1924, and the structure was a basic resistance-bridge type accelerometer (Walter, 2006). By 1936 an improved 2-axis accelerometer became available on the market, and the main uses for it were identified in the aircraft industry, the steam turbine industry, and the underground tunnel industry (Walter, 2006). Accelerometers did not become commercialized on a large scale until 1941, and this can be seen to be credited to Arthur Ruge and Edward Simmons and their addition of the bonded resistance strain gage to the accelerometer (Walter, 2006). Even more recently, the production of a 3-axis accelerometer has begun, and it is this technology that is most predominant in accelerometers today. The basic anatomy of an accelerometer consists of an outer shell, a spring, a mass and circuitry (Noton, 2011). The basic use of an accelerometer is for measuring acceleration, however it can also be used for measuring activity (Jonathan, 2006), and it is this use that has become the most useful in sporting and fitness settings. There are two main kinds of accelerometers; the analog accelerometer and the digital accelerometer. The digital accelerometer is more advanced than the analog one, one of the reasons behind this is that the digital accelerometer is more stable, and it is able to produce a direct output signal, which the analog accelerometer is unable to do (Jonathan, 2006). Ultimately, accelerometers measure proper acceleration, often measured in terms of g forces, and can be used to measure a whole range of human activities, from running and dancing, to skipping and walking (Jonathan, 2006). The technology used in modern accelerometers, as is used within the Nike+ Fuel Band, is a triaxial technology, that allows for simultaneous measurement of vibration in 3 perpendicular axis (Weber, 2012).