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Juerg Feldmann

Fortiori Design LLC
Posts: 1,530
We  have an ongoing    process of discussing   reactions  of MOXy in involved  and non involved muscle groups.
 We  could also ask:  important   or less important muscle groups.
  Example. In ice hockey the legs    seem to be more involved in the overall action than the arms. So is the respond  to defend  oxygenation  in the legs  more important  than maintaining O2  in the arms.
 On the other side  we  argue , that respiration is more important   than  moving, so if respiration is    pushed to the limit the    deoxygenation    will happened n the legs  to  protect the  more vital  respiration.
 Here    an interesting study supporting our  points.

Related trends in locomotor and respiratory muscle oxygenation during exercise.

Author information

  • 1Laboratory of Human Movement Studies, Faculty of Sports Sciences and Physical Education, Lille University, Lille, France.



We investigated the potential effect of respiratory muscle work on leg muscle oxygenation without artificial intervention in non-endurance-trained young subjects and searched for the range of intensity when this effect could occur.


We simultaneously monitored accessory respiratory and leg muscle oxygenation patterns with near-infrared spectroscopy (NIRS) in 15 healthy young men performing maximal incremental exercise on a cycle ergometer. Pulmonary gas exchange was measured. The respiratory compensation point (RCP) was determined. Oxygenation (RMO2) and blood volume (RMBV) of the serratus anterior (accessory respiratory muscle) and of the vastus lateralis (LegO2 and LegBV) were monitored with NIRS. The breakdown point of accessory respiratory muscle oxygenation (BPRMO2) and the accelerated (BP1LegO2) and attenuated fall (BP2LegO2) in leg muscle oxygenation were detected.


BPRMO2 occurred at approximately 85% .VO2max and was related to RCP (r = 0.88, P < 0.001). BP2LegO2 appeared at approximately 83% .VO2max and was related to RCP (r = 0.57, P < 0.05) and with BPRMO2 (r = 0.64, P = 0.01). From BP2LegO2 to maximal exercise, LegBV was significantly reduced (P < 0.05).


In active subjects exercising at heavy exercise intensities, we observed that the appearance of the accelerated drop in accessory respiratory muscle oxygenation-associated with high ventilatory level-was related with the attenuated fall in leg muscle oxygenation detected with near-infrared spectroscopy. This suggests that the high oxygen requirement of respiratory muscle leads to limited oxygen use by locomotor muscles as demonstrated in endurance-trained subjects. The phenomenon observed was associated with reduced leg blood volume, supporting the occurrence of leg vasoconstriction. These events appeared not only at maximal exercise but onward above the respiratory compensation point.

Now here  2 test  supporting  this as well   courtesy of Jiri. Example of a  drop in  trapezius  and  leg  SmO2. As well as a high CO2  which would  support the O2  disscurve shift to the right  and enhances the drop in SmO2

Richterovw CO2  and SmO2 trends.jpg 

  And here an example of  an athlete  from the same group. where  respiration may not be taxed  to the limit  and therefor   stable O2  but  leg muscels  got pushed  so they have a higher utilization , than

  Jili CO2 Smo2.jpg 

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