MATLAB: Time Normalisation of vertical ground reaction force

Question

Hi everyone. I have vertical ground reaction force data during running and have trials of different lengths so I'm looking to time normalise to 100%

Answer 1

This is a job for interp1:

Signal     = rand(1, 1000);  % Test data
HeelStrike = 72;
ToeOff     = 413;
Contact    = Signal(HeelStrike:ToeOff);
ConatctN   = interp1(1:numel(Contact), Contact, linspace(1, numel(Contact), 101));

Now the ground contact phase is normalized to 101.

If this is a bottleneck in your code, use FEX: ScaleTime:

ContactN = ScaleTime(Signal, HeelStrike, ToeOff, 101);