Once something rolls it can roil fast.
MOXY is one of this intriguing new tools and any critical coaches or fitness centers has the same questions as we. What can we do to improve assumptions and calculations of physiological zoning to be more accurate for individual people.
Well NIRS and MOXY are one new direction.
So we have from many different places now people seeing the potential and go and spread the word and make connection. Here is one short inside view in a discussion with a very progressive country in Europe pushing always limitations and developing since centuries top notch physiological
So some of the answers may benefit more than one or the other person.
Hi Roger and Juerg,
I had my visit to YYY this week and it went well. We made a demo and they found Moxy interesting and they probably want to purchase one or two for research purposes. They made a few questions where I did not have an answer immediately, so maybe you can give me an answer to the following questions:
1. As they are research people, they asked about validation of the device. Is there any validation study coming in the near future?
Near Infrared Spectroscopy (NIRS)
C. Dean Kurth MD
Cincinnati Children’s Hospital
Professor of Anesthesia and Pediatrics
University of Cincinnati College of Medicine
Determination of the accuracy of the NIRS devices has been problematic. In order to determine accuracy, the device must be compared with a gold standard. Because there is no gold standard for NIRS (ie, no other device measures O2 saturation in the tissue circulation), determination of accuracy remains an estimate. There is currently one FDA approved device, made by Somanetics. Its accuracy on the FDA application was compared relative to a weighted average (SwO2) of arterial and jugular bulb O2 saturation. In adults and children, the device is not that accurate (+10-15%) on an absolute level of oxygenation (rSO2 vs SwO2), but is fairly accurate (+5%) on a change in oxygenation ( rSO2 vs SwO2). In other words, the device indicates a change in oxygenation accurately but does not indicate accurately what the oxygenation actually is.
Other devices purport greater accuracy than the Somanetics device. However, these devices are not FDA approved, not commercially available, and have not been subject to accuracy testing on large scale. Nevertheless, several of these devices have been tested in animal models and have been found to be accurate +3% on an absolute.
a) one of the practical application validation is the proper occlusion test.
If a NIRS device is usable you should see a drop of SmO2 to zero in a proper applied occlusion test. See att of three occlusion test. Only one was done properly and you see that in a proper occlusion test the tHb will be flat stable . so no intake and no outflow.
The middle one was done by Andri
2. Measuring through fat layer. How can it be known that fat layer is not affecting the reliability of the measurement? This is also a question from me, because I have had a couple of tests where the SmO2 values have been around 90% for the entire test and have not decreased much during the test.
Roger has to get into this details.
The fact is, that if there is certain amount of subcutaneous fat we loose signals. The penetration depth with the way the ligth is emitted is app. 12 mm.
Values of 90 % and little change.
This can be a sign of not setting a signal through, but you would see that possible as well in the high tHb values. ( Roger has to correct me on here if that is wrong ) BUT it is physiologically absolute possible , that people load perfect but really can't desaturate because of the O2 Diss curve Hypocapnic respiratory reaction. 2 option you can use to verify, whether it is the fat layer or whether it is the persons physiology.
1. Reduce the load down to where he or she felt really good so for sure no problem.
Normally you would see an increase in SmO2 but if it is already high nothing happens.
Now you tell the person to breath in, hold the breath as long as possible and slowly breath out a little bit and again breath deep on and hold the breath.
At the same time you use an SpO2 finger sensor and you look SmO2 reaction.
If it is a problem of O2 diss curve you now will move the curve to the right side so O2 will be easier let go from Hb and Mb but harder to load. So you should see a d rop in SpO2 on the finger and a drop in SmO2 in the MOXY area. If the flat SmO2 is around 70 you can do the easier way you let the person breath very fast and lot's of air to get rid of CO2 and you will see an increase in SmO2 as O2 Disscurve shifts to the left. You can try this on yourself. Mount a MOXY on a biceps . lift the arm look reaction. Than hyperventilate and see what happens with SmO2.
2. So there is a simple test you do in this cases in an endurance sport. If you finish the test on the bike or run and you see little of no drop in SmO2 you take the person off the endurance equipment and let them do for example a one leg squatting activity if the MOXY is on the leg.
If it is on the stomach you can do a abdominal exercise, if it is on the biceps you do a biceps curl. just a very simple local overload where you always will see a drop or you can go brutal and make an occlusion . The SmO2 will always drop if the reading is there under this situations. ( with some very very rare situations of specific diseases like mitochondriosis. for example..
3. Measurement in different locations. Would it make sense to measure at the same time in different muscles? If the right leg of a cyclist is stronger than the left leg, would the readings in Moxy be different?
Yes in an endurance test I always use 2 moxy's but possibly fun as well in a strength workout.
Back up if one goes wrong.
As we do not look always the actual number but the trend you will see the same.
See att active and non active muscles same trend and see in the forum what we believe happens. Yes there are nice studies done by Cooper and we did many years back the same just never published on asymmetry in sport . see att.
Thanks for giving me some help for these questions!