Sign up Latest Topics
 
 
 


Reply
  Author   Comment  
Juerg Feldmann

Fortiori Design LLC
Registered:
Posts: 1,530
 #1 
Hi Juerg

Just a small and easy question for you.

Yesterday I just sat down and put the Moxy on the upperside of my Vastus lateralis and let it there for 1 minute. Than I moved it to the middle of the Vastus lateralis and let it there for 1 minute again. Then moved it further down below to the low side of the Vastus lateralis and let it there for 1 minute again. What I mean with further down is moving it further down towards the position of the knee (you could also say from North to South [wink]

I did this 4 times just to see if I could see trends.

My observation was:

The further down you go on the Vastus Lateralis the more bloodflow (higher tHb) and the less SmO2 (and vice versa when you go higher up)

Is that consistent with your findings in people as well? And what is actually the ''logical'' explanation for that (if there is a logical explanation)?

As you can see I also did a simple biceps thing. Put Moxy on my biceps for 1 minute. Then 1 minute put my finger on my arterties/veins to block the flow. Then let go and see what happened in that minute again.

It's fun just to do these things and see what happens

And here the  great  picture.

vast lat  bic  +  biceps.jpg

Now teh next fun part on thsi is  whne  we do teh same  but during activities.
 As  Ruud is a  cyling  fan  even more fun is  to  do thsi with three moxy's  and use   a GURU  bike fitting bike so you chnage  different parameters    as you bike like seat handle bar distance, hip angle  and so on  and you can  actually see, what happens as  youy mionatin fixed wattage  and  thna chnage this. WEe  even  chnaged  teh  pedla lenght to get some feedback on teh ongoing discussin on  optuimal pedal lenght  and we  even change  cleat positions  from  toes  towards heels  and  had  MOXY's  and SEMG  on calf  and quad ricspes  and hamstromgs   and intercaostal muscels.
  A lot  of  interestg  informations  and  I ma sure teh cycling community  will earlier thna  later    start  to use MOXY as  an additiopnal tool  for   biek fitting  as well as   otehr   interesting opitons ,. For us   it will be a lot's  of  fn to see teh result s sform teh Pro  from teh cycling commuynity and see, whether they  make teh same conclsuoon as we  do.
 I had  a few month back  soem interesting conversions  about a    bllod  flow  problem in a top cyclists    and  I gto teh MOXY  information to   try to see, whetehr I woudl pcik teh p[roper  leg  side.
.  My answer was I  do nto know  and explain  what we need  and  what coudl be teh    information we see  from what we  have.
 To my surpsie was  that I got a very fast interpretation n which leg is teh problem  form onen of teh most    famous  bike  gurus  (  with teh samll  propbem that he missed  teh leg  which was  affected    well 50 %  chnacce. )  Sp lot's  to do  and to leanr  for all of  us  and as Ruud  points  out  we cna leanr faster  by sharing information. In some cases  thsi is very hard  to    achieve  so    we hoep  over time   that is  what we  can d on thsi forum  as    some regular   readers  show  with thir incredible openness to share  ides  and information. So here a big THANK  YOU RUUUD  you are teh best !!!!
  So here    for all thansk to Ruud  some interesting  stuff  toread  and  it may  particllay  explain what we see in Ruud's  case. 

 A method for assessing heterogeneity of blood flow and metabolism in 2exercising normal human muscle by near infrared spectroscopy

 

Ioannis Vogiatzis1,2, Helmut Habazettl,3,4, Zafeiris Louvaris1,24 , Vasileios

Andrianopoulos2, Harrieth Wagner5, Spyros Zakynthinos2 , Peter D. Wagner 5,6 5

 

 Faculty of Physical Education and Sport Sciences, National and Kapodistrian University of

Athens, Greece 8

 Department of Critical Care Medicine and Pulmonary Services, Evangelismos Hospital, "M.

10 Simou, and G.P. Livanos Laboratories", National and Kapodistrian University of Athens, Greece

 Institute of Physiology, Charité Campus Benjamin Franklin, Berlin, Germany

Institute of Anesthesiology, German Heart Institute, Berlin, Germany

Department of Medicine, University of California San Diego, La Jolla, CA, USA

 Institute of Clinical Exercise & Health Sciences, University of the West of Scotland, UK

 Running Head: Regional muscle VO2/Q heterogeneity in exercising healthy humans

Corresponding author: Dr. Ioannis Vogiatzis, Faculty of Physical Education and Sports Science,

Ethnikis Antistasis Street, 17237, Athens, Greece. Tel: +302107235521; Fax: +302107239127;

e-mail: gianvog@phed.uoa.gr.

Articles in PresS. J Appl Physiol (January 15, 2015). doi:10.1152/japplphysiol.00458.2014

Copyright © 2015 by the American Physiological Society.

Abstract

Heterogeneity in the distribution of both blood flow and O2 consumption (VO2) has not been

assessed by Near Infrared Spectroscopy (NIRS) in exercising normal human muscle. We used NIRS to measure the regional distribution of blood flow and VO2 in six trained cyclists at rest and during constant load exercise (unloaded pedaling, 20%, 50% and 80% of peak watts) in both normoxia and hypoxia (FIO2=0.12). Over six optodes over the upper, middle and lower vastus lateralis, we recorded: a) indocyanine green dye inflow after intravenous injection to measure blood flow (Q), and b) fractional tissue O2 saturation (StO2) to estimate local VO2/Q ratios. Varying both exercise intensity and FIO2 provided a (directly measured) femoral venous O2 saturation (SfvO2) range from about 10 to 70%, and a correspondingly wide range in StO2. Mean Q-weighted StO2 over the 6 optodes related linearly to SfvO2 in each subject. We used this relationship to compute local muscle venous blood O2 saturation from StO2 recorded at each optode, from which local VO2/Q ratios could be calculated by the Fick principle. Multiplying regional VO2/Q by Q yielded the corresponding local VO2. While six optodes along only in one muscle may not fully capture the extent of heterogeneity, relative dispersion of both Q and VO2 was about 0.4 under all conditions, while that for VO2/Q was minimal (only about 0.1), indicating in fit young subjects: a) a strong capacity to regulate blood flow according to regional metabolic need and b) a likely minimal impact of heterogeneity on muscle O2 availability.

 

Key words: Near Infrared Spectroscopy, Exercise, Muscle Blood Flow, Oxygen Uptake


Ruud_G

Development Team Member
Registered:
Posts: 279
 #2 
Skin thickness / fat / depth the light goes plays a role?
Juerg Feldmann

Fortiori Design LLC
Registered:
Posts: 1,530
 #3 
Yes  an most likely  much more. There is a  summary of  NIRS  usage  over the last  few years  and I think it was  done by Ferrari  et all  and they made a great list of  all  points  you have to  look at when  using NIRS  for research ideas  and  quantitative  conclusions. In other words  using NIRS  and use   with it a lot  of assumption  to  hope some of the metrics  we  can find  ate  decently correct. As   practical users    with  meaningful use  of  MOXY in the field  for  all of  us, this points  are well taken  but   the  practical coach  better  learns  to forget et absolute metrics  and looks     when using MOXY  at trends  only   but for sure trends in tHb   and individual trends   on one person  as well as  trends  an d over time  some absolute values  on individual  people  rather than  any of  the  great but highly complex    and based on assumptions  metrics. MOXY is a practical tool  for us  to use as a live feedback. Will try to trace it down in my mess
Juerg Feldmann

Fortiori Design LLC
Registered:
Posts: 1,530
 #4 
Okay here  I found  it as a  short  summary of the great article.

REVIEW

The use of near-infrared spectroscopy in

understanding skeletal muscle physiology:

recent developments

BY MARCO FERRARI1,*, MAKII MUTHALIB2 AND VALENTINA QUARESIMA1

1Department of Health Sciences, University of L’Aquila, L’Aquila, Italy

2School of Human Movement Studies and Movement Neuroscience Program,

Institute of Health and Biomedical Innovation, Queensland University

of Technology, Brisbane, Queensland, Australia

This article provides a snapshot of muscle near-infrared spectroscopy (NIRS)



Table 2. Recommendations for near-infrared spectroscopy muscle studies. ATT, subcutaneous

adipose tissue thickness; CW, continuous-wave spectroscopy; EMG, electromyography; FD,

frequency-domain spectroscopy; fMRI, functional MRI; MRI, magnetic resonance imaging; NMR,

nuclear magnetic resonance spectroscopy; SRS, spatially resolved spectroscopy; PET, positron

emission tomography; TD, time-domain spectroscopy. topic current status recommendations

depth sensitivity typically approximately 1.5 cm for 3–4 cm source–detector distance. Measurements

restricted to superficial muscle(s) use TD technologies and tomographic approaches for improving depth sensitivity. In the case of multi-distance CW–NIRS, use less than 5mm and greater than 30mm for the shortest and

longest source–detector distance, respectively investigated muscle volume and measurement points

oxygenation of large muscle groups like the quadriceps is investigated by using only one or two measurement points

use multi-channel systems for investigating the spatial profile of muscle/muscle groups oxygenation

optode positioning often not accurately reported describe in detail the location,

eventually guided by ultrasound scanner

optode–skin coupling/sliding; optode sliding owing to sweat (especially in hairy skin) and/or mechanical factors

often not verified during and after the study or not mentioned

ensure an adequate stable contact between the optodes and the skin throughout the acquisition session. Minimize the sliding by bandage (avoiding venous occlusion), and use NIR transparent double-sided adhesive tape.

 

MOXY   very early on accepted  our  advice in giving up on a  circular   system to  fix  MOXY on the skin. So  we avoid pressure  socks  or  garments  and  fix it with a  tape on the tested area. In fact  Roger  produced  a double sided  option  for MOXY  adjustment

 

 

moxy-adhesive-attachment.png

Monitor the pressure of the optode on the skin adipose tissue thickness often not reported measure ATT using skinfold callipers, ultrasound scanner, MRI or optical lipid signal. Eventually perform studies only on subjects with homogeneous ATT. Use algorithms for ATT correction skin blood flow changes over the exercising muscle

usually not measured measure skin blood flow (e.g. by laser Doppler) and/or skin temperature close to the optode

in prolonged exercise muscle shape changes during exercise usually not mentioned try to keep the limb movements in the same planes in order to minimize artefacts. Artefacts should be identified and corrected/eliminated in the NIRS

data analysis exercise and experimental set-up description often inaccurate describe in detail the protocol for

the reproducibility/repeatability of the measurements  topic current status recommendations kinematic motor

performance motor performance not always monitored and controlled monitor motor performance by three-dimensional kinematic analysis in particular for open field exercise absolute quantification value of NIRS

measures SRS–CW-based systems provide only SmO2 (%) quantification use TD- and FD-based instrumentations for improving sensitivity and quantitation of NIRS parameters data analysis analysis of SmO2 (%) and concentration changes in O2Hb, HHb and tHb. Often only the HHb kinetics and amplitude are analysed and reported analyse and report all measurable parameters, i.e. O2Hb, HHb, tHb, SmO2 standardization no standardization is available for NIRS instrumentation/signal processing/data analysis regulatory authorities or network of research laboratories should provide ‘guidelines’ multi-modal studies very few studies integrate NIRS with MRI, fMRI, NMR, PET, EMG, microdialysis, Doppler blood flow measurements

 

5. Future directions

The most exciting prospect of muscle NIRS studies for the next 20 years is

the full understanding of skeletal muscle biochemistry/physiology/pathology for

improving human healthcare, athletic performance and rehabilitation monitoring.

The major challenge to achieving this understanding might be the availability

of a low-cost, easy-use optical wearable/wireless non-contact NIR imager for

obtaining four-dimensional SmO2 and haemodynamic (blood flow and tHb)

measurements of human skeletal muscle, especially during dynamic exercise.

This ideal ‘NIR imager’ should be suitable for any application (including

general health, clinical and athletic settings), and might be an addition to the

current heart rate monitoring and lactate measurements during training in the

field and health centre-like environments. This ideal ‘NIR imager’ should be

combined/integrated with other imaging and electrophysiological modalities for

enhancing the understanding of specific muscle mechanisms in pathophysiological

conditions.

Considering the rapid development of related technologies, it is very difficult

to predict the potential advancements of muscle NIRS and NIR imaging. The

quantitative measurement of deep forearm oxygenation and tHb by a non-contact

oximeter prototype was proposed by Niwayama et al. [45].

The current typical depth sensitivity of most CW-based imagers is

approximately 1.5 cm. Therefore, a tomographic approach might provide

three-dimensional SmO2 and haemodynamic measurements. Blood flow of

Phil. Trans. R. Soc. A (2011)

12 M. Ferrari et al.

the superficial muscles might be continuously measured by diffusing-wave

spectroscopy, a new rapidly progressing technique discussed in an accompanying

symposium paper. Although three-dimensional NIR imaging of the human

forearm, based on TD techniques, was proposed by Hillman et al. [46] almost

10 years ago, no further progress has been made to develop the technique.

In conclusion, it is foreseeable that the availability of advanced NIR imagers

would help to refine the understanding of skeletal muscle oxygenation in different

pathophysiological conditions.

The research is supported in part by Hamamatsu Photonics KK, Japan.

How independent  should research be ?

Previous Topic | Next Topic
Print
Reply

Quick Navigation:

Easily create a Forum Website with Website Toolbox.

HTML hit counter - Quick-counter.net