COP velocity vs COP excursion

[Daan van Kooten]

Hello everyone,

I am working with forceplatedata and Center of Pressure (COP) values in order to determine the dynamic gait variabillity within stance phase. In literature they sometimes use COP velocity and sometimes excursion. What are differences between those values and which one is the best to use? or should I use both?

Thanks,
Daan

[Lærke Lindskov]

Re: COP velocity vs COP excursion

I haven't worked with CoP data but isn't excursion a measure of displacement and velocity the differentiation of this?

/Lærke

[Daan van Kooten]

Re: COP velocity vs COP excursion

I haven't worked with CoP data but isn't excursion a measure of displacement and velocity the differentiation of this?

/Lærke

The excursion of the CoP position data is the |maximum value| + |minimum value|. While the velocity is indeed the differentiation of the position data. Both parameters are used as measures for movement variabillity. My problem is that I don't know which one is the 'best' parameter of dynamic gait variabillity?

[Dany Lafontaine]

Re: COP velocity vs COP excursion

If I may add a little detail to the posts above...

COP velocity is the differentiation of position data, while COP excursion is linked to the trajectory of COP. In fact, COP excursion is more of a medio-lateral displacement metric. If you trace a line from initial point of contact to toe-off, the distance of the COP relative to that line is really what is meant by excursion. As such, both metrics can be used as a means to assess gait variability but linked to different causes/issues. COP velocity can be used to assess variability in duration of contact phase, COP excursion can help in assessing variability in where the contact is being made underfoot (medial or lateral column of the foot).

Hope this helps!!