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Asked by Seth
on 16 May 2013

Im looking to write a script that will automatically work out the jump height from force platform data measuring at 1000Hz. The code I have so far is:

r = find(truedata==0,1,'first'); % find when first 0 occurs truedata = (truedata(1:r+1,6)*-1); % cut data bw = mean(truedata(1:20,1)); % find body weight Jbw = bw*(r*(1/1000)); % work out impulse caused by body weight t = [0:1/1000:r/1000]; % change in time Jall = trapz(t,truedata); % calculate impulse of whole graph impulse = (Jall-Jbw); % calculate jump impulse vel = (impulse/(bw/9.81)); % calculate take off velocity jumpheight = ((vel^2)/(2*9.81)); % equation of motion This however is not giving me the correct answers, could anyone see a problem in my calculations?

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## 4 Comments

## Walter Roberson (view profile)

Direct link to this comment:http://www.mathworks.com/matlabcentral/answers/76070#comment_149388

Is "bw =" really on the same line as the "% cut data" ?

I suspect you have not copied the code properly.

## bym (view profile)

Direct link to this comment:http://www.mathworks.com/matlabcentral/answers/76070#comment_149402

that does not help... look for the {code} button to format your code so that it looks like this:

and so on...

A short sampling of truedata would be helpful as well

## Seth (view profile)

Direct link to this comment:http://www.mathworks.com/matlabcentral/answers/76070#comment_149405

it should read:

## Walter Roberson (view profile)

Direct link to this comment:http://www.mathworks.com/matlabcentral/answers/76070#comment_149407

The code Seth posted runs lines together. It is not a {code} formatting issue, more newlines are needed to make sense of the code.