Vertical ratio incorrect calculated by Garmin

Hi, here the pictures I am refering to:

Garmin definition of stride length --> stride length = step length.   Which is incorrect. 

Run with HRM pro plus --> step length = 0,77 cm. So in formula vertical ratio step length is used = incorrect. 

Run with Wahoo Tick R --> Wahoo records stride length and populates field step length with value.  So in formula vertical ratio stride length is used = correct. 

Fer said:

As commonly known step = distance between keft and right foot, stride = distance between the same foot (+/- x2 step length)

Can you provide a citation for this?

I've never seen a stride referred to as two steps before (and I've been around a few decades). Maybe this is a country specific definition but in UK English a stride is defined as [noun] 'a long, decisive step' or [verb] 'walk with long, decisive steps in a specified direction'.

Is there an accepted definition for vertical ratio published somewhere?  

I think you should obtain the same result for vertical ratio, regardless of whether you use a single or two foot falls as your definition for stride length (assuming you run with left/right symmetry).  Would not vertical oscillation be doubled if your definition of stride is two foot falls (one bounce per foot fall, so 2x)?  If so, then ratio is roughly the same regardless of definition.

Fer said:

If you google step length vs. stride length you will find a lot about the difference.

I was hoping you may have had a definitive definition from a sport governing body. My Google search returned evidence for either method. (I only looked at two pages of results but they all appeared to be USA based.)

What I did see noted several times is that Garmin uses the convention of one stride equals one step across for their devices.

Fer said:

Do you agree stride is 2 steps?

I don't think I can answer that definitively as it appears which you use depends on the activity.

I've done a lot of walking over the years (I can remember when you measured distance with a piece of string on a paper map) and for me and those I walked with it was one stride equals one step. I only started running regularly a few years ago and have kept using the walking definitions.

Hi,

Thanks for your answer back. 

Vertical ratio is vert. osc. / stride length.  The ¨problem¨ lies in the definition of a stride: 1 step left to reight foot or 2 steps left to left foot.  

I have added an example with Garmin stridelength = steplength and Wahoo stride length above (2nd post).  There you can see what increased stridelength fogure does with the vertical ratio result.  

I was triggered by the two different values of stride length between Wahoo and Garmin. 

Kr,

Fer