IDIAG MOXY | EN

Moxy measures two parameters that are interlinked; SmO2 and tHb. The way in which these parameters change we are informed about the muscular relationship between the supply and demand oxygen. If SmO2 increases supply is greater than demand. If SmO2 decreases supply is less than demand. If SmO2 remains relatively stable or unchanged oxygen supply and demand is equal.

SmO2 or muscle oxygen saturation is a relationship measure between oxygenated hemoglobin (O2Hb) and deoxygenated hemoglobin (HHb). Using NIRS the Moxy measures in a relative form (not quantifiable) the amount of hemoglobin present in the muscle under the sensor. Specifically, it differentiates between the amount of haemoglobin carrying oxygen and the amount of haemoglobin that is not carrying oxygenation. This results in the following formula: O2Hb / HHb + O2Hb = SmO2.

tHb is a relative measure (not quantifiable) of the total amount of hemoglobin that is passing underneath the sensor and is therefore the bottom portion of the SmO2 formula above (O2Hb + HHb). THb is an indirect indicator of blood volume change.

tHb is an indirect measure of blood volume. If the following assumptions are made an increase in tHb is a result of increased blood volume under the sensor. We must first assume that the amount of hemoglobin per dl of blood in the human body remains stable, and the concentration of hemoglobin per dl of blood during the measurement remains constant. Important is to note that tHb does not necessarily show blood flow.

The SmO2 parameter is a bioenergetics parameter. Oxygen is a primary component for energy production in the muscle and therefore SmO2 is a bioenergetics parameter that is most effectively applied to training focussing on bioenergetics. This involves the production of energy in the muscles as the limiting factor. This is the case for most forms of extended or repeated exercise from HIIT to steady state exercise. Where SmO2 as a parameter are not optimally used is in, for example, guidance of 1RM.

Comparison between Moxy parameters (SmO2) and traditional performance diagnostics methods have been made, including comparisons between muscle oxygenation and blood lactate, and muscle oxygenation and ventilatory threshold. Both show good correlations. This makes sense in that all these parameters are linked to one another directly or indirectly.

Resting SmO2 can vary greatly between individuals and between muscles, ranging from 40%-90%. At the moment we do not analyse resting parameters and consider them individual. At rest cardiopulmonary work and muscle work is very low, and therefore both supply and demand for oxygen is low. This means little change in either supply or demand can have a major effect in SmO2, until the counterpart of the supply and demand relationship responds.

The Moxy Monitor measures at a depth of 15mm. If adipose tissue on the measurement site exceeds 15mm getting correct measurements is extremely difficult as the infrared lights fails to pass through muscle tissue. If dealing with an individual where you are unsure if the 15mm depth is sufficient, consider this in your analysis of the data. Large adipose layers will result in less extreme changes in SmO2 and higher SmO2 values. This means that trending information may still be accurate when assessing an athlete, but the values of SmO2 will likely be inaccurate.

SpO2 or saturation of peripheral oxygenation is measured via a pulse oximeter. It measures the saturation of oxygen in the pulsating blood or in other words the arterial blood. Arterial blood is always highly saturated as it has not passed through a muscle where it would be used in metabolism. The Moxy SmO2 parameters ignores the pulsating blood and only looks at the deeper capillary blood vessels and therefore measures muscle blood oxygenation rather than arterial blood saturation.

As explained in the definition of SmO2, SmO2 is muscle oxygen saturation, this being the amount of relative oxygenated hemoglobin against relative total hemoglobin. Tissue saturation on the other hand is the amount of relative oxygenated hemoglobin against relative total hemoglobin in all tissue under the sensor, not just muscle. This means it includes skin layer and adipose tissue. Obviously this will influence the measurement value that the user needs to be aware of when applying to training.