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runner

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 #1 
Is there a direct correlation between SmO2 and electromyography (EMG)
in endurance sports like running and cycling?

Does muscle oxygen desaturation correspond to equal increased
EMG?

Kirill

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Posts: 94
 #2 
[image] 

https://www.researchgate.net/publication/283155489_Determination_of_aerobic-anaerobic_transition_in_the_working_muscle_using_EMG_and_near-infrared_spectroscopy_data
juergfeldmann

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 #3 
Great  discussion and nice  to see the use  of  combination a  suggested   on this forum since many years. What  would be nice is, if they not just limit  on 2  like in this case, but add  as  so often suggested  cardiac hemodynamic  and   blood values, as well as  respiratory feedback  so   we can see how our ideas finally moving  back to a  simple  tool like NIRS  can be justify.
 
One more to add. SmO2  alone is not optimal as  used here  as  the  tHb  as well has some interesting  connections to  SEMG. This  for sure when we move away  from just bike  testing and go more into a local rehabilitation use of   individual muscles. There  SmO2  and SEMG  can  give some wrong  feedbacks, if we not combine it with tHb. 

runner

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Posts: 59
 #4 
> cardiac hemodynamic  and   blood values, as well as  respiratory feedback

Is there a simple practical example where knowing hemodynamics values or
respiratory frequency/volume would make a difference in reading SmO2/ThB
graphs?

If SmO2 and EMG are highly correlated, it seems that EMG may be redundant.
NIRS gives you both SmO2/ThB while EMG only allows you to infer SmO2.

Is there a case where having EMG values is beneficial or preferrable over
SmO2?
juergfeldmann

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 #5 
Is there a simple practical example where knowing hemodynamics values or
respiratory frequency/volume would make a difference in reading SmO2/ThB 
graphs?

Yes look  at  the  Nick Mclean  example in the other thread.

Is there a case where having EMG values is beneficial or preferable over 
SmO2?

Yes we know  that  SmO2   recovery trends under specific  situations are  very  close  to CrP  recovery. But if  we  create a  " flat" SmO2  in an all out  load  and tHb  is  flat or increasing  further  than we   need  SEMG.
A )  
 Crp.  in   this cases   we see  whether  we have a  change in SEMG  due  to an intermuscular  change  and still a  maintaining of    activity in the tested  muscle .
 In  some cases we see SmO2  showing a " nice " recovery  " but Cr.P  and SEMG  not.
Even  thb  than  has different options in the recovery depending on limiter.  Below  the abstract of  an old  study  we   repeated  with  different tools.
 

Resynthesis, while Muscle pH and EMG Amplitude Remain Depressed

Alberto Mendez-Villanueva,1,2,* Johann Edge,2 Rob Suriano,2 Peter Hamer,2,3 and David Bishop2,4

Conrad P. Earnest, Editor

Author information ► Article notes ► Copyright and License information ►

This article has been cited by other articles in PMC.

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Abstract

The physiological equivalents of power output maintenance and recovery during repeated-sprint exercise (RSE) remain to be fully elucidated. In an attempt to improve our understanding of the determinants of RSE performance we therefore aimed to determine its recovery following exhaustive exercise (which affected intramuscular and neural factors) concomitantly with those of intramuscular concentrations of adenosine triphosphate [ATP], phosphocreatine [PCr] and pH values and electromyography (EMG) activity (a proxy for net motor unit activity) changes. Eight young men performed 10, 6-s all-out sprints on a cycle ergometer, interspersed with 30 s of recovery, followed, after 6 min of passive recovery, by five 6-s sprints, again interspersed by 30 s of passive recovery. Biopsies of the vastus lateralis were obtained at rest, immediately after the first 10 sprints and after 6 min of recovery. EMG activity of the vastus lateralis was obtained from surface electrodes throughout exercise. Total work (TW), [ATP], [PCr], pH and EMG amplitude decreased significantly throughout the first ten sprints (P<0.05). After 6 min of recovery, TW during sprint 11 recovered to 86.3±7.7% of sprint 1. ATP and PCr were resynthesized to 92.6±6.0% and 85.3±10.3% of the resting value, respectively, but muscle pH and EMG amplitude remained depressed. PCr resynthesis was correlated with TW done in sprint 11 (r = 0.79, P<0.05) and TW done during sprints 11 to 15 (r = 0.67, P<0.05). There was a ∼2-fold greater decrease in the TW/EMG ratio in the last five sprints (sprint 11 to 15) than in the first five sprints (sprint 1 to 5) resulting in a disproportionate decrease in mechanical power (i.e., TW) in relation to EMG. Thus, we conclude that the inability to produce power output during repeated sprints is mostly mediated by intramuscular fatigue signals probably related with the control of PCr metabolism.

 

Summary: 
 Depending how  complex  you like to go   the answer is no:  SEMG is  great  for  SEMG  and NIRS  is great for  NIRS , that's  what they are designed  for.
 If  you go more mainstream  than  YES  NIRS  where  you have tHb reactions  can  give you a  lot of  SEMG   trend information when you  combine it  with  the  needed  physiological reactions  discussion.  Remember both  are very local feedbacks. With NIRS on a nonpriority muscles  we  can get  more  feedbacks, but with a SEMG on a nonpriority muscle  we  get  no real feedback   due to what it can measure  .



juergfeldmann

Development Team Member
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Posts: 1,501
 #6 
Here a  fun old study  Martina Feldmann did  many years back , when we where looking  whether there is a connection between lactate  and SEMG  and respiration. 
 Key thoughts.
 Respiration  will change  due  to CO2 , CO2  will change due  to lactate   buffer  help  H +  shuttle  and  SEMG  may change  due  to  change in intramuscular  coordination as   intramuscular  coordination may change  due  to ATP   to low  risk.  ( Conett et all ). rather   than increasing   the idea to try to create more ATP  the    body will reduce  the  risk or  option  to use  ATP )

mart lac.jpg

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