algorithm/macro for working with long data column

I am new here so please take it easy on me!

I have a column of data (time series) which happens to be ankle angle measured during walking. There are 6000 data in the column which represents about 100 steps.

I want to calculate the range of motion for each step - that is, minus the minimum angle from the maximum angle for each step.

My major problem is how to use excel to 'define' each step - so that I can calculate a separate maximum and minimum. In other words, I need to be able to split the column into multiple arrays which represent each step.

In the attached file I have noted the first stride on a graph with two red bars and used the stars to highlight the two points I need (the maxima and minima of that range). I have noted that each stride seems to be about 50 samples long. Ideally I would like to have this number located in a cell so that I could change it and see the effect on the calculations (for example it will be a shorter range if used on running data).

Hope that makes sense.

Thanks for any help.

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EDITED THIS TIME ONLY

Originally Posted by murf58

In the attached file I have noted the first stride on a graph with two red bars and used the stars to highlight the two points I need

I can't see that in the current attachment I'm afraid - just the data points.

Originally Posted by murf58

I have noted that each stride seems to be about 50 samples long. Ideally I would like to have this number located in a cell so that I could change it and see the effect on the calculations (for example it will be a shorter range if used on running data).

This is a key point - so are you saying you intend to base each step on this arbitrary input cell (eg 50) as opposed to using some logic or other to establish each step separately based on the 6000 data points ?

If that is the case then what you want to do should be relatively straightforward - you just need to use an INDEX (or Volatile OFFSET) statement to create the various ranges for use in conjunction with MIN/MAX.

If we assume (using sample) that C1 holds 50 (step value) then:

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With the above in place (to help us identify how many calcs need to be performed) then:

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C2:C351 can be copied to D2:D351 with MIN changed to MAX.

As you alter C1 you should find that the results in C2:D2 onwards adjust accordingly.