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fellrnr

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 #1 
I'm seeing very little change in tHb, far less than I would have expected. Most workouts the tHb only varies between 13.05 and 13.15, which is less than 1% variation. 

Is that what's expected?

(I'm seeing a tHb range from the Humon sensor of 15 to 18, which is ~20% variation.) 
Roger

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 #2 
Hi fellrnr,

The THb value is arbitrarily scaled.  The Moxy number seems to be more narrowly arbitrarily scaled than Humon number.

It's used to tell if blood volume in the muscle is increasing, decreasing, or staying the same.  The magnitude typically isn't useful.

Roger
fellrnr

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 #3 
If I scale up the Moxy tHb, I seem to get more noise than data. Below, Orange is Moxy, green is Humon. 



4-29-2019 2-48-28 PM.jpg

fellrnr

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 #4 
Here's another example. You can see power at the bottom in green. The Humon tHb in blue rises during the warm up, then responds to the power changes in a plausible way. The Moxy tHb drops during the warm up (which is not what I'd expect), but then doesn't seem to relate to the intervals. 

4-29-2019 2-59-09 PM.jpg 

bjrmd

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 #5 
I recently did a comparison of the Bsx, Hex and Moxy data values (on my blog). Although I don't personally have the Moxy, my friend the Xcskier does and shared some data using it with the Hex. For the most part, they are tracking in a similar fashion. There is a heavy smoothing algorithm on the Hex making it look less noisey. Could your unit be defective?
CraigMahony

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 #6 
The Hex is typically placed over the RF. Did you also place the Moxy over the RF or put it in over the VL which is the position frequently used? If you did this may account for the difference in readings. I get very different trends in the RF to the VL when cycling.
fellrnr

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 #7 
@CraigMohony. I place both sensors in mirror positions, left/right. I've swapped them over a number of times without different results just in case I had some wild imbalance. I typically use the VL.

@bjrmd. I'm seeing very similar SmO2 from Hex and Moxy, though the dynamic range of the Moxy is greater, and has less smoothing. The tHb are completely different, with the Moxy not reading any trends. I was wondering about a problem in my unit, but that seems weird given the SmO2 looks fine. 


bjrmd

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 #8 
You could try a different area - put either the Moxy or Hex on a biceps or triceps, then do an arm curl or body weight dip.  I had very good correlation with those.  The VL can be a finicky spot for several reasons, the RF is a better choice at high intensity (more recruitment).

If the Moxy is not brand new, do you have older data from your Moxy showing better THb trends?

Quote:
I was wondering about a problem in my unit, but that seems weird given the SmO2 looks fine.


Yep.
bobbyjobling

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 #9 
Don't forget that IR penetration for the NiRS devices in the tissue could be different due to the LED power and tech used.
Also I find the pressure applied to keep the sensor in place has an effect on the THb trend.

fellrnr

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 #10 
I tried the Moxy and Hex on the RF. I got a little more change in the tHb for Moxy, but still more noise than data.
5-2-2019 9-34-40 AM.jpg 

I did some dips with them on my triceps, which given my lack of upper body strength was quite intense. 

5-2-2019 9-37-53 AM.jpg 


bjrmd

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 #11 
I took a look at your tracings and one of the sensors THb just does not make sense (in blue)
The black arrows are presumably the start stop (my guess):
dip.png 
The O2 desats are fine but after a set of body weight dips, you should see a massive reperfusion/hyperemia.

Here is what mine looks like with the Hex and BSX:
BSX on tri dip.png  Hex on tri dip.png  The BSX is a better tracing since it does not have a running average built in.

You may want to ask for a sensor exchange.


fellrnr

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 #12 
Thanks! I would also expect a massive increase in blood flow between resting and exercise (I see the figure of 20x increase often quoted.) 


ryinc

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 #13 
Could you comment on Moxy orientation. i found that placing the device "horizontally" (i.e. power button would not be on top or bottom but rather facing left or right) seems to get better data results?

Otherwise i would contsct Roger directly. He is very helpful in trouble shooting.
ryinc

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 #14 
As an aside a "u shaped" thb has been discussed on the forum - and does present in a number of athletes dats. .So the macro shape may not be unreasonable.
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