Using Near-Infrared Spectroscopy (NIRS) to Determine Lactate Threshold

Posted by Stuart Giere on Mon, Jul 23, 2012 @ 11:07 AM

journal of strength and condition researchA letter from the CEO of Fortiori - Makers of the Moxy Monitor:

In September of 2009, the Journal of Strength and Conditioning published a paper titled "Using Near-Infrared Spectroscopy to Determine Maximal Steady State Exercise Intensity."  The authors of the paper (Snyder and Parmenter, University of Wisconsin-Milwaukee) discuss a study they performed on 9 men and 7 women using a medical version of the Moxy Monitor, in this case referring to the metric as SmO2 (Muscle Oxygen Saturation). 

In the paper, Snyder and Parmenter state that "Maximal steady state (MSS) speed can be determined from blood lactate concentration (HLa); however, this method is not optimal.  (Lactate requires a finger stick blood sample).  The purpose of this study was to determine whether Near-Infrared Spectroscopy (NIRS) technology could be used to detect a breakpoint in percent oxygen saturation (SmO2) of the muscle and whether the determined breakpoint exercise intensity could be used to determine MSS exercise intensity."

The testing protocol included "Sixteen distance runners and triathletes ... they completed an incremental exercise test. A change from linearity when plotting SmO2 or HLa (Lactate) vs. running speed was defined as the breakpoint."

"The subjects then completed constant speed runs to determine maximal lactate steady state (MLSS). In 12 subjects, breakpoints were identified for both HLa and SmO2 values." the paper goes on to say.  This work was all done on a treadmill with the Smo2 sensor on the calf muscle of the athlete.

Snyder states that "The results of this study lead us to conclude that the NIRS determination of SmO2 is a noninvasive technique that is comparable with HLa (Lactate) in determining MSS intensity and therefore appropriate for use in determining exercise training intensity." 

In other words, using Near-Infrared Spectroscopy to determine lactate threshold, or Maximal Steady State exercise intensity (the pace at which a runner or triathlete can sustain long distances without running out of energy, and without pacing too slowly), is an "appropriate" methodology.  And it is real-time, continuous, and non-invasive - which you can't get with HLa (Blood Lactate) systems.

SmO2 during workout

The team at Fortiori is driving hard to bring the Moxy Monitor to market, and get this tool into the hands of athletes that would benefit from direct and instantaneous feedback as to what is happening in their muscles during exercise.

Maximizing the efficiency of athletes’ workouts, and the progress towards their performance goals, will always be the top priority of the Fortiori team.

Thank you,

Stuart Giere is co-founder and CEO of Fortiori. Stuart graduated from South Dakota State University with a degree in engineering, and now lives in the greater St. Cloud Area with his family. Still working as an engineering manager, Stuart was previously employed at Hutchinson Technology, where he was the director of engineering, responsible for overseeing various engineering, marketing, sales, and new business development initiatives. Stuart has years of experience leading teams to launch high- technology products and medical devices.

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Image courtsey of Journal of Strenght and Conditioning Research


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