I'm working on paired data, of which absolute values plotted over time, show periodicity with varying peak heights as shown in the following graph:
The data represent the absolute distance between two feet, so peaks are maximum steplengths.
Both the blue and red line belong to the same participant that moves in different environments (red: virtual reality; blue: reality).
I need to compare each data to its counterpart and I am wondering which of measures of center, mean, median or the mode, is an appropriate representative value for the varying peak heights of such type of data?
Purpose of comparison: Discovery of difference between step lengths in reality compared to step lengths in virtual reality.
I have thought of z-transforming the data in order to make peak variance more comparable in addition to a measure of center - But I'm not sure if this is a sufficient representation of the data?