Aportaciones al estudio de la oxigenación muscular durante el ejercicio físico mediante espectrometría de infrarrojo cercano

Resum

Objectives To determine the influence of gender, anthropometric and ergo-spirometric factors on muscle oxygenation of quadriceps and twins obtained by NIRS in young adults. In addition, to analyze the differences in SmO2 of quadriceps and hamstrings muscles, in several phases of a maximum effort test according to sex. As well as to analyze the SmO2 values obtained in several phases during a maximum effort test, in a group of recreational athletes over 45 years old who practice Nordic Walking. Methodology The methodology has been divided into three blocks. Each block corresponds to an objective, in which a different population and its own method have been described. For the first and second blocks, the sample was composed of students from the University of Murcia and for the third, adult recreational athletes. A common methodology to these three blocks has been detailed, placing the subjects, according to the study, with various Humon Hex¿ devices in the twin, quadriceps and hamstrings muscles, to collect muscular oxygen saturation (SmO2) during a stress test. A specific protocol was used in each study. The first and second objectives executed a stress test on a treadmill (model run7411) with a continuous and progressive ramp protocol. Meanwhile, objective three performed a modified Bruce ramp protocol. Likewise, the electrocardiographic recording was continuously monitored with a Cardioline¿ electrocardiograph and the maximum oxygen consumption (VO2 max (Metalyzer 3B)) was measured. In addition, data corresponding to anthropometric assessment and body composition were collected and related to SmO2 values. Results - SmO2 has a negative relationship with the fat percentage, that is, the higher the percentage of fat, the lower the SmO2 and this is higher in women. - At the time of maximum effort, there are significant differences between men and women in the SmO2 of the ischiosural muscle (p<0.05). In addition, the correlations between SmO2 values and anthropometric variables show that the thigh crease is negatively correlated with the saturations of both muscles at the moment of maximum effort, likewise the thigh contour also correlates with the SmO2 of the ischiosurals. - The SmO2 value presents a negative relationship with the heart rate and oxygen consumption, decreasing during exercise. Conclusions - The SmO2 assessment of the subjects in the first study is influenced by both the location of the device and the fat mass and with greater differences between males and females in the twins. - An inverse relationship with the subject&apos;s fat and SmO2 is shown. In addition, the latter is different in the ischiosurals for men and women at the time of maximum effort. - The evolution of SmO2 is opposite to that of heart rate and oxygen consumption, decreasing during exercise and increasing in recovery. Key words: near infrared spectrometry, exercise, oxygen consumption, gastrocnemius, quadriceps, maximal exercise testing, nordic walking