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Juerg Feldmann

Fortiori Design LLC
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Posts: 1,530
 #1 
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.

Source

Department of Neurological, Neuropsychological, Morphological and Exercise Sciences, School of Exercise and Sport Sciences, University of Verona, Italy.

Abstract

PURPOSE:

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).

METHODS:

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.

RESULTS:

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.

CONCLUSIONS:

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.

 

 

S.M.

Development Team Member
Registered:
Posts: 65
 #2 
Fascinating stuff.  It doesn't take long working with the Moxy to see it's value.
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