Hi all,

This may be the wrong forum/section to post this problem in, the problem I have is, calculating the onset of a displacement of the Vertical Centre of Mass. This data that I have is for a person that is in a standing position, with infrared markers on them, this gives us the Centre of Mass Z/vertical distance from the capture Volume. When the person begins to sit down the COMz displaces/decreases rapidly. This is easy to spot on a graph, as you get a contstant "ish" COMz for x time, then all of a sudden they begin to sit down and the COMz falls sharply. We call this phase the onset of Acceleration. We currently have the COMz data with the time that each event is occuring, I would like to be able to mathematically determine, when the graph starts to drop??? Any Ideas at all?
Many thanks in advance
Leo