1. A method of analyzing repetitive motion, comprising: accessing image data that tracks a user performing a repetitive motion; analyzing the image data to determine a plurality of data points for a parameter, the data points are for different points in time; forming a parameter signal of the parameter versus time, the parameter signal tracks the repetitive motion; dividing the parameter signal into a plurality of repetitions of the repetitive motion; and analyzing a first repetition of the plurality of repetitions in the parameter signal using a signal processing technique.