EMG cycloergometry

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EMG cycloergometry

Post by domc34 » Mon Nov 06, 2017 4:42 am

Hi, few months ago I did an EMG on vastus lateralis and vastus medialis of one of my students while doing a cycloergometry protocol, in which Watts are going up every minute after the warming up. Here I post the experiment.

I have some questions.
If I want, for example, to correlete the RMS quantity from the two muscles activity vs Watts. Do i have to select all the activity?, the maximun peak value of the RMS?, the area of the peak?

There are some artifacts that we detected on the raw signals and we are sure that the electrodes were not unnatached or hiting against the cable, etc. Is it correct if I deleted that signals and do the quantification only whit the signals that are left?

When I do the spectrum analysis, I would like to overlap the frequency analisys of every minute of the experiment, does the sofware has that option?


Grettings from Mexico ;)
Ciclo ergometro EMG FE 2.adicht
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Re: EMG cycloergometry

Post by tbroughton » Tue Nov 07, 2017 8:55 am

Hi there,

On the topics of whether your analysis protocol is correct or not, I'll leave this to other forum members - we at ADInstruments can't tell you what type of analysis is best, that is up to you to decide.

On the topic of overlaying the Spectrum, you cannot specifically overlap by time directly as such.

One would define what FFT Window you like to set in terms of the FFT size in data points (1024 data points, 512 data points etc) instead. For example if you set your FFT size to 512 and selected 1536 data points in your Chart View, you'd split this data into 3 Windows (each of width 512) in the Spectrum - you could then decide on the Overlap for these FFT Windows.

25%, 50%, 75%, 87.5% or 93.75% Overlap are available, which means that each successive FFT overlaps with the previous one by the selected percentage, or you can choose No Overlap.

Overlapping ensures all data are represented and a larger overlap smooths the spectrum in the time dimension. Overlapping gives more accurate results, but doubles the computation time.

For example, if No Overlap was chosen, a data selection of 1024 points with an FFT size of 512 points would be divided into two segments: points 1-512 and points 513-1024. If 50% Overlap were chosen for the same data, the segments would change to points 1-512, points 256-768 and points 513-1024.

I hope that helps.
Tom Broughton
Education Support Specialist | ADInstruments Europe

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Re: EMG cycloergometry

Post by domc34 » Tue Nov 07, 2017 8:20 pm


Thanks for your answer, I´ll be figuring out how to get the best results