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Juerg Feldmann

Fortiori Design LLC
Posts: 1,530
One of our  interesting task over all this years  is to find an option to close the gap between  science in the lap  and the  grass root user outside in the field.
 We  are  absolutely aware  that  there will be many compromises  to be made to move  the great  development of  information's we now can gather in labs into the field.

 There is  no discussion anymore, that using live data  are  the way to go as they are  LIVE  and individual  and that   scientific  statistic  are great   but have the limitation of  any statistic.
 220 -  age . %  VO2  max.   lactate threshold  ideas  and so on.
 No wonder there is a  rush  out there to develop bio markers  we can see live  like HR  as  the oldest one, now  more an more  respiratory feed backs  since the  start   by Zephyr  with the bioharness and the latest  kid  in the block  is  NIRS  as it is now cheap available  and   you can use a  watch like  a garmin watch  with SmO2  and tHb  live numbers  nd graph..
 So   we  are getting closer to end  speculations  and usemathematical formulas  and can replace them  with live feedback.
  A  super interesting situation is the section we see developing in cycling, where they  use the W  bal  we discussed on other areas here.
 Great concept  great  ideas   great theory  and great calculations.
 BUT not live  as  real  feedback  from the  muscles.
 So  to close the gap between this ideas and  NIRS we need some papers who show how they  connect  with each other.
  So here the picture  of closing the gap  followed  by some intriguing studies  to show  that  NIRS/MOXY  may just be the   real  deal  for live feedback  instead of calculations  and hope.

closing the gap.jpg 

paper  on  recovery  W. bal  and   real substrate  like Pcr.

Intramuscular determinants of the ability to recover work capacity above critical power



PurposeThe primary purpose of this investigation was to compare the recovery of the W′ to the recovery of intramuscular substrates and metabolites using 31P- and 1H-magnetic resonance spectroscopy.

MethodsTen healthy recreationally trained subjects were tested to determine critical power (CP) and W′ for single-leg-extensor exercise. They subsequently exercised in the bore of a 1.5-T MRI scanner at a supra-CP work rate. Following exhaustion, the subjects rested in place for 1, 2, 5 or 7 min, and then repeated the effort. The temporal course of W′ recovery was estimated, which was then compared to the recovery of creatine phosphate [PCr], pH, carnosine content, and to the output of a novel derivation of the W′BAL model.

ResultsW′ recovery closely correlated with the predictions of the novel model (r = 0.97, p = 0.03). [PCr] recovered faster (t12 =38s)than W′(t12 =232s)The W′ available for the second exercise bout was directly correlated with the difference between [PCr] at the beginning of the work bout and [PCr] at exhaustion (r = 0.99, p = 0.005). Nonlinear regression revealed an inverse curvilinear relationship between carnosine concentration and the W′t1/2 (r2 = 0.55).

ConclusionThe kinetics of W′ recovery in single-leg-extensor exercise is comparable to that observed in whole-body exercise, suggesting a conserved mechanism. The extent to which the recovery of the W′ can be directly attributed to the recovery of [PCr] is unclear. The relationship of the W′ to muscle carnosine content suggests novel future avenues of investigation.


 Now  look here the interesting  trend  between  SmO2  and PCr  and combine the W'   with  PCr  and SmO2.

A cross-validation of near-infrared spectroscopy measurements of skeletal muscle oxidative capacity with phosphorus magnetic resonance spectroscopy

Terence E. Ryan , W. Michael Southern , Mary Ann Reynolds , Kevin K. McCully

Journal of Applied Physiology Published 15 December 2013 Vol. 115 no. 12, 1757-1766 DOI: 10.1152/japplphysiol.00835.2013



The purpose of this study was to cross-validate measurements of skeletal muscle oxidative capacity made with near-infrared spectroscopy (NIRS) measurements to those made with phosphorus magnetic resonance spectroscopy (31P-MRS). Sixteen young (age = 22.5 ± 3.0 yr), healthy individuals were tested with both 31P-MRS and NIRS during a single testing session. The recovery rate of phosphocreatine was measured inside the bore of a 3-Tesla MRI scanner, after short-duration (∼10 s) plantar flexion exercise as an index of skeletal muscle oxidative capacity. Using NIRS, the recovery rate of muscle oxygen consumption was also measured using repeated, transient arterial occlusions outside the MRI scanner, after short-duration (∼10 s) plantar flexion exercise as another index of skeletal muscle oxidative capacity. The average recovery time constant was 31.5 ± 8.5 s for phosphocreatine and 31.5 ± 8.9 s for muscle oxygen consumption for all participants (P = 0.709). 31P-MRS time constants correlated well with NIRS time constants for both channel 1 (Pearson's r = 0.88, P < 0.0001) and channel 2 (Pearson's r = 0.95, P < 0.0001). Furthermore, both 31P-MRS and NIRS exhibit good repeatability between trials (coefficient of variation = 8.1, 6.9, and 7.9% for NIRS channel 1, NIRS channel 2, and 31P-MRS, respectively). The good agreement between NIRS and 31P-MRS indexes of skeletal muscle oxidative capacity suggest that NIRS is a valid method for assessing mitochondrial function, and that direct comparisons between NIRS and 31P-MRS measurements may be possible.


 What are the possible thoughts  you can make ?

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