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juergfeldmann

Development Team Member
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 #1 
This is  an ongoing stream of  emails I am getting.
 Can we use the   break pint  of  SmO2  or  HHb  or  O2Hb   and  simply replace  with it  the lactate threshold ?

 Here my  answer.
  NIRS is a direct feedback  and lactate is a  indirect feedback  with more  questions in the blood concentration we  test  at the finger than answers  from what  muscles and form where we may have gotten the  lactate concentration., We  discussed this  to  the never ending  ideas. So no point  starting again.

 What  we  thought originally is  exactly this  with delay.
 What we found in hundreds  of test  and hundreds  of  test using  NIRS on the same leg on different muscle bellies on quadriceps  or on different leg muscles , that  break points  can appear  but they  do not have to appear  and there  are many reasons  why.

 What we know is, that the protocol we  may design can create  break points  for that  specific idea  but  can not be used in any other ideas in the field. So shorter  steps  with higher increase in loads  more likely  will create  a break point. Changing technique  as well. Change  from  heel strike to fore foot  as  runner  and your calf will tell you this. Change saddle height on a bike and your quadriceps  will tell you something.

What seems to be more likely is, that  main muscle groups  involved in a  specific  activity more likely  will show  drops in SmO2  or  increase in HHb  or  drops in O2 Hb  compared  with less  involve muscle groups. ( exception  you have a  systemic  delivery limitation )  To  try to talk myself  out of  trouble  here some of many studies  looking  at this   questions.


Differences between the Vastus Lateralis and Gastrocnemius Lateralis in the Assessment Ability of Breakpoints of Muscle Oxygenation for Aerobic Capacity Indices During an Incremental Cycling Exercise

Bangde Wang,1,2* Guodong Xu,3,4* Qingping Tian,1,2* Jinyan Sun,1,2* Bailei Sun,1,2* Lei Zhang,1,2* Qingming Luo,1,2* and Hui Gong1,2*

1Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics

2Key Laboratory of Biomedical Phototonics of Ministry of Education, Huazhong University of Science and Technology, Wuhan, China

3School of Physical Education, Jianghan University, Wuhan, P.R.China

4College of Health Science, Wuhan Institute of Physical Education, Wuhan, China

Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, China

 

Received May 9, 2012; Accepted July 17, 2012.

Abstract

In recent years, breakpoints (Bp) of muscle oxygenation have been measured in local muscles using near infrared spectroscopy (NIRS) to assess (predict) systemic aerobic capacity indices [lactate threshold (LT), gas exchange threshold (GET) and maximal oxygen uptake (VO2peak)]. We investigated muscular differences in the assessment (predictive) ability of the Bp of muscle oxygenation for aerobic capacity indices during incremental cycling exercise on the aerobic capacity indices. Thirty-one active college students were recruited for an incremental cycling exercise test, during which NIRS muscle oxygenation in the vastus lateralis (VL) and gastrocnemius lateralis (GL), blood lactate concentration and cardiopulmonary variables were measured simultaneously in a multi-modality approach. A linear regression model was used to analyse the relationship between the Bp of the muscle oxygenation index (OI) and the systemic aerobic capacity indices. The Bp of the muscle OI in both the VL (BpVL) and GL (BpGL) were significantly correlated with the aerobic capacity indices. Additionally, the BpVL had a better goodness-of-fit [higher coefficient of determination (R2, p < 0.001) and lower root mean squared error (RMSE, p < 0.03)] in the linear regressions and occurred earlier than the BpGL

. In conclusion, both the BpVL and the BpGL could be measured by NIRS to assess the systemic aerobic capacity indices; however, there were muscular differences in the assessment ability of the Bp of muscle oxygenation.

Key points

  • The breakpoints (Bp) of muscle oxygenation index in both vastus lateralis (VL) and gastrocnemius lateralis (GL) could be detected to indicate the breaking up of the oxygen supply-consumption balance by NIRS.
  • The Bp of muscle oxygenation index in both VL (BpVL) and GL (BpGL) were significantly correlated with the systemic aerobic capacity indices.
  • The BpVL owned higher assessment (predictive) ability when the Bp (BpVL and BpGL) of muscle oxygenation index was used to assess (predict) systemic aerobic capacity indices.

 Or



Muscular differences in breakpoints of muscle oxygenation changes

Considering that the VL and GL were mostly studied independently in previous NIRS studies, we tested the VL and GL simultaneously to compare the two muscles, as the VL and GL are involved as a knee extensor and a knee flexor/ankle stabiliser, respectively, during cycling. The BpVL appeared earlier than the BpGL (p < 0.001), indicating that the oxygen supply-consumption balance in the VL was broken earlier than that in the GL during cycling IET. Furthermore, the BpVL had higher assessment ability (indicated by the higher R2a and lower RMSE, Table 2) for the aerobic capacity indices than the BpGL. One reason for the differences in the Bp of OI between the VL and GL might be the differences in anatomical and histochemical characteristics. Sufficient evidence has shown that the percentage of type I (slow twitch) fibres in the VL is lower than that in the GL (Edgerton et al., 1975; Houmard et al., 1998; Staron et al., 2000). Additionally, the activity of oxidative enzyme (citrate synthase) was previously reported to be lower in the VL than that in the GL (Houmard et al., 1998). Due to the lower percentage of type I fibres and lower activity of oxidative enzymes in the VL, the fast twitch fibres would be largely recruited earlier in the VL when the workload continuously increases, resulting in more anaerobic metabolism in the VL during moderate and high intensity exercise. The earlier accumulation of acidic metabolic substances in the VL might result in more H+ and a lower pH. Due to the Bohr effect, the accelerated dissociation of O2Hb would occur earlier in the VL due to the earlier accumulation of acidic metabolic substances; this result is indicated in our data by the earlier breaking up of the oxygen supply-consumption balance in the VL (BpVL). Another reason for the differences in the Bp of OI between VL and GL might be different usage patterns of the muscles during cycling. The mono-articular muscles (e.g., the VL) are primarily involved in the generation of positive work, whereas the biarticular muscles (e.g., the GL) are responsible for regulating force transmission during cycling (So et al., 2005). Additionally, the VL is thought to be one of the most active muscles during cycling (Hug et al., 2006) and seems to produce more muscle work than the GL over the crank cycle (Neptune et al., 2000). Therefore, the contribution of the VL is most likely higher than that of the GL during cycling, which might account for the earlier occurrence of the BpVL and the higher assessment ability of the BpVL for the aerobic exercise capacity indices. In summary, the differences in the BpVL and the BpGL might be mostly associated with the muscular differences in the percentage of muscle fibres and the usage patterns during cycling. However, further research with muscular biopsy and/or sEMG is needed to confirm this type of association.

 

Muscular differences in breakpoints of muscle oxygenation changes

Considering that the VL and GL were mostly studied independently in previous NIRS studies, we tested the VL and GL simultaneously to compare the two muscles, as the VL and GL are involved as a knee extensor and a knee flexor/ankle stabiliser, respectively, during cycling. The BpVL appeared earlier than the BpGL (p < 0.001), indicating that the oxygen supply-consumption balance in the VL was broken earlier than that in the GL during cycling IET. Furthermore, the BpVL had higher assessment ability (indicated by the higher R2a and lower RMSE, Table 2) for the aerobic capacity indices than the BpGL. One reason for the differences in the Bp of OI between the VL and GL might be the differences in anatomical and histochemical characteristics. Sufficient evidence has shown that the percentage of type I (slow twitch) fibres in the VL is lower than that in the GL (Edgerton et al., 1975; Houmard et al., 1998; Staron et al., 2000). Additionally, the activity of oxidative enzyme (citrate synthase) was previously reported to be lower in the VL than that in the GL (Houmard et al., 1998). Due to the lower percentage of type I fibres and lower activity of oxidative enzymes in the VL, the fast twitch fibres would be largely recruited earlier in the VL when the workload continuously increases, resulting in more anaerobic metabolism in the VL during moderate and high intensity exercise. The earlier accumulation of acidic metabolic substances in the VL might result in more H+ and a lower pH. Due to the Bohr effect, the accelerated dissociation of O2Hb would occur earlier in the VL due to the earlier accumulation of acidic metabolic substances; this result is indicated in our data by the earlier breaking up of the oxygen supply-consumption balance in the VL (BpVL). Another reason for the differences in the Bp of OI between VL and GL might be different usage patterns of the muscles during cycling. The mono-articular muscles (e.g., the VL) are primarily involved in the generation of positive work, whereas the biarticular muscles (e.g., the GL) are responsible for regulating force transmission during cycling (So et al., 2005). Additionally, the VL is thought to be one of the most active muscles during cycling (Hug et al., 2006) and seems to produce more muscle work than the GL over the crank cycle (Neptune et al., 2000). Therefore, the contribution of the VL is most likely higher than that of the GL during cycling, which might account for the earlier occurrence of the BpVL and the higher assessment ability of the BpVL for the aerobic exercise capacity indices. In summary, the differences in the BpVL and the BpGL might be mostly associated with the muscular differences in the percentage of muscle fibres and the usage patterns during cycling. However, further research with muscular biopsy and/or sEMG is needed to confirm this type of association.

   Or  look at the great  webinar  by  Dr. A. Coggan on the MOXY  website.

Ruud_G

Development Team Member
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Posts: 279
 #2 
Well. Since starting NIRS related to breakpoints. Here's one that integrates a multitude of breakpoints.

http://www.researchgate.net/profile/Silvia_Pogliaghi/publication/271523459_Exercise_Intensity_Thresholds_Identifying_the_Boundaries_of_Sustainable_Performance/links/552e0db30cf2e089a3ad97f6.pdf?inViewer=true&disableCoverPage=true&origin=publication_detail

Conclusion
The current study has demonstrated that the concepts of CP, MLSS, RCP, and [HHb]BP may be unified by determining the VO2p (rather than the PO) associated with each functional index of exercise intensity substantiating the existence of a “metabolic boundary” partitioning heavy from very heavy exercise domains. These data suggest that the CP, MLSS, RCP, and [HHb]BP constructs may be physiologically equivalent and, providing optimal design and appropriate determination, each could theoretically represent the highest VO2p at which [La]b (and VO2p ) can be stabilized, and thus the “boundary” of sustainable versus unsustainable constant-power exercise. This is of valuable practical importance as the interchangeability of each index may provide exercise physiologists, sport scientists and clinicians with a number of options for determining the limits of tolerable endurance exercise depending upon the test population, the available resources and the desired intensity target for exercise prescription.

By the way they measured it on the Vastus Lateralis

Now what would be nice is TIPS which include VO2 measurements, etc to see those markers all moving together.
juergfeldmann

Development Team Member
Registered:
Posts: 1,501
 #3 
Ruud  thanks  so much.

Now what would be nice is TIPS which include VO2 measurements, etc to see those markers all moving together

  This is  exactly  what we did  when we combined initially  cardiac feedback  and respiratory  feedback  and blood feed backs  and NIRS  and SEMG. Can we see a  connection  and what is the easiest  way to avoid  all this equipment   and use  it simple and practical.
 I showed some of this somewhere in the forum  from far back , so here  some  as an  encore.  I just finished  a  2 hour  discussion  with friends and we  exactly had this point as a  discussion.
There is much more out there than  cycling  and MAX lass and CP  and FTP . There is a huge group of people  simply moving  and  are activity in any   way  they can. So they do not have  wattage or  any performance option or  not a great objective performance option, so the  easiest way to find their   activity  steady state load is  by using  live NIRS. So MOXY  as such is an actual  sport tool   showing you live feedback and telling you where you are in you activity in your intensity  level  too easy  too hard  or balanced. Than  it adds the feedback  on  why  , if it is balanced  it is balanced  and  who fails  that we are out of  balance  Limiter and compensator. T find this you simply need  to   use  MOXY live. You can start with a  simple biceps  curl. Go  easy  and  maintain delivery  and you can go  a long time. Go harder and find a balance and go very hard  and stop delivery and  an end  point will arrive  earlier than later.

This is of valuable practical importance as the interchangeability of each index may provide exercise physiologists, sport scientists and clinicians...

Exactly  so it comes  to a very simple  question. or  questions:
  1. Fitness center  training center or  any  group  which makes  assessments  or  some may name it  test.  Do you use  a  10.000  dollar  good  but not perfect VO2  equipment  to  find  again  the steady state. an dhow can you use this during workouts   for  your customers  and   problem  with  masks  and so on.
  O r do you  use blood values  with all the  risk  and permission you really  would need and how  do you use it practical.
  Or  do you use  a NIRS  which   can only be sued   for  cycling or  running but for nothing more than  this   . Do you have a NIRS  you can us e on   many  people  as it is  what it is NI RS.
 So here a  very different    look to this  a business look.
 Charge  150  dollar  per assessment  as you pay  for any current assessment  but you get all that  out what we discuss .
 Charge  100 $  for an assessment  and test 4  people at the same time . So   1000 $   equipment cost  for a  MOXY  is   an incredible smart investment and you are even a head of the  competition  and have no hassle  and  more direct feedback and even use the same  assessment tool  for  live practical workouts  as  feed backs. ?
 Seems to be a no brainer  as well as  it is what we discuss all the time the search  for   the   energy needs  delivery and demands  and why not  measure  what w talk about O2     now as you can do it now directly. ?


Here  to make it easier to look at   three graphs  with cardiac  feedback , respiratory  feedback  and NIRS  feedback from the same assessment  courtesy   Andrea    from the beautiful Swiss Ticino.

cardio ex.jpg 



  resp info ex.jpg 
NIRS ex.jpg 



Simple  question. What  can you use  in the field practical  and still have the  real feedback on this days under this conditions  that you  have a sustainable  speed  or  performance .
 Any  answer  is  appreciated on what  current tools  you  can use.    So  you run through the forest, you bike  of  road, you play a tennis  game ,  you  row   your sea kayak,  you    play a soccer  game.  you  do some double poling imitation  with an elastic  in the forest  and so on. 

What  tool  can  do that  now  ???

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