I am in a very interesting discussion with a group in NZ.
Their take on intensity is, that MAX LASS or maximal lactate steady state is a great tool to use to find an optimal intensity.
So their question is, whether the MOXY could find the MAX LASS ???
Their point is :
If that would be possible there would be a no brainer to change form an invasive relative complex test idea to a simple noninvasive MOXY assessment.
First perhaps the following thoughts.
1. Lactate as we learned in the "classical' idea of Mader et all 2 and 4 mmol It is most likley for most of the people a no go this days. There is ample of evidence, that this statistical information is not working and was a great start at the time in the 1980 area.
. We all most likley will agree, that absolute lactate values, no matter what you think is the truth on lactate is not working for intensity control or zoning.
We all agree, that it is impressive if I take blood as it looks very scientific.
If that is the justification we are in a bad situation with exercise physiology.
So IF we take lactate today for intensity control the idea of a MAX LASS is most likely the most accepted one.
Problem: We find one single " Zoning " based on MAX Lass an thats it , the rest is again a speculation based mostly on experience.
Now what does MAX LASS mean, when we look at the whole picture ??
It means, that metabolically we have reached a situation, where the ATP production requires different energy sources and one pathway of the ATP production will create lactate and depending of the function an the amount of the lactate we will see it in a balances situation, where we see no drop in lactate as well as no increase.
. This would mean that the energy production and the energy utilization are in this specific balance metabolic situation.
So when we look at MOXY we would have a flat SmO2 situation and yes MAX LASS and flat SmO 2 would accrue at tech same time.
Now we know by now , that we can have a flat SmO2 on different levels depending on other situations.
The " last " Flat (plateau ( intensity we can see with MOXY is where we have a " MAX LASS" Situation.
The problem is, that any influence over for example respiration will change the lactate trend. ( example slow and deep breathing versus fats and shallower. but as well we will see a change in SmO2.
So to the original question. Yes when we look at the SmO2 trends and we have a Plateau over a certain time ( at least 10 + min we will most likley see there a stable lactate value.
Whether this is the Max Lass is an open question.
Now there are studies done claiming this. here one so you see, that it is not from our kitchen. It is from our friends in Italy
Determination of maximal lactate steady state in healthy adults: can NIRS help?
Bellotti C, Calabria E, Capelli C, Pogliaghi S.
Department of Neurological, Neuropsychological, Morphological and Exercise Sciences, School of Exercise and Sport Sciences, University of Verona, Italy.
We tested the hypothesis that the maximal lactate steady state (MLSS) can be accurately determined in healthy subjects based on measures of deoxygenated hemoglobin (deoxyHb), an index of oxygen extraction measured noninvasively by near-infrared spectroscopy (NIRS).
Thirty-two healthy men (mean ± SD age = 48 ± 17 yr, range = 23-74 yr) performed an incremental cycling test to exhaustion and square wave tests for MLSS determination. Cardiorespiratory variables were measured bbb and deoxyHb was monitored noninvasively on the right vastus lateralis with a quantitative NIRS device. The individual values of V˙O2 and HR corresponding to the MLSS were calculated and compared to the NIRS-derived MLSS (NIRSMLSS) that was, in turn, determined by double linear function fitting of deoxyHb during the incremental exercise.
V˙O2 and HR at MLSS were 2.25 ± 0.54 L·min (76% ± 9% V˙O2max) and 133 ± 14 bpm (81% ± 7% HRmax), respectively. Muscle O2 extraction increased as a function of exercise intensity up to a deflection point, NIRSMLSS, at which V˙O2 and HR were 2.23 ± 0.59 L·min (76% ± 9% V˙O2max) and 136 ± 17 bpm (82% ± 8% HRmax), respectively. For both V˙O2 and HR, the difference of NIRSMLSS from MLSS values was not significant and the measures were highly correlated (r = 0.81 and r = 0.76). The Bland-Altman analysis confirmed a nonsignificant bias for V˙O2 and HR (-0.015 L·min and 3 bpm, respectively) and a small imprecision of 0.26 L·min and 8 bpm.
A plateau in muscle O2 extraction was demonstrated in coincidence with MLSS during an incremental cycling exercise, confirming the hypothesis that this functional parameter can be accurately estimated with a quantitative NIRS device. The main advantages of NIRSMLSS over lactate-based techniques are the noninvasiveness and the time/cost efficiency.