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* These authors contributed equally
This protocol integrates near-infrared spectroscopy (NIRS) technology to assess localized hematological and oxygenation changes at the prefrontal cortex, respiratory (m.Intercostales), and locomotor (m.Vastus Lateralis) muscles during cardiopulmonary exercise testing, enabling the identification of central and peripheral limiting factors affecting exercise performance.
The gold standard to assess the aerobic capacity in physically active subjects and athletes is the maximal oxygen consumption test (VO2–max), which involves analysis of exhaled–gases and cardiorespiratory variables obtained via the breath-by-breath method in an ergospirometer during an incremental exercise. However, this method cannot elucidate metabolic changes at the muscular level. Near-infrared spectroscopy (NIRS) has emerged as a valuable technology to evaluate local oxygen levels (Tissular Saturation Index, TSI) by quantifying the concentrations of oxygenated (O2-Hb) and deoxygenated (H-Hb) hemoglobin in the microvasculature of tissues. NIRS applications extend to respiratory and locomotor muscles, assessing metabolic changes associated with the cost of breathing (COB) and peripheral workload, respectively. Additionally, cerebral regions, such as the prefrontal cortex, have been explored with NIRS technology to assess physiological changes related to cognitive demand associated with planning or ideation of motor tasks linked to sports performance. Thus, by analyzing exercise-induced changes (D) in O2-Hb, H-Hb, and TSI, it is possible to identify central and peripheral exercise limitations, particularly when endurance training is the main component of physical fitness (e.g., running, cycling, triathlon, etc.). Addressing these factors is paramount for coaches and exercise physiologists to optimize athletic performance, incorporating training strategies focused on the primary exercise-limiting factors. This study outlines a protocol for utilizing wearables devices equipped with NIRS technology to analyze exercise changes in TSI, O2-Hb, and H-Hb, alongside cardiorespiratory variables typically registered in athletes during VO2–max tests. This approach offers a comprehensive method for identifying the primary systems involved in stopping exercise progression and sports performance improvement.
Endurance athletes rely on an efficient balance of oxygen delivery and uptake to sustain high–intensity exercise and enhance their athletic performance1,2. The maximal oxygen uptake test (VO2-max) is a vital physiological assessment that determines sports performance by analyzing exhaled–gases and cardiorespiratory variables during incremental exercise intensity1. This assessment, known as ergospirometry or Cardiopulmonary Exercise Testing (CPET), reflects the exercise response of the cardiovascular, respiratory, and muscular systems3. Alon....
The protocol was approved by the Institutional Review Board of the Pontificia Universidad Católica de Chile (projects nº 210525001 and 220608010), and the study was conducted in accordance with the Declaration of Helsinki. All participants provided written informed consent before participating in the testing described.
1. Placement and setup of NIRS wearables
NOTE: Various NIRS wearables and data acquisition software can be utilized. Researc.......
During the completion of a CPET, the symptoms of dyspnea, leg fatigue, and rate of perceived exertion (RPE) were reported in all subjects. The complementary use of the NIRS devices did not add any discomfort to the subjects' sensation assessment. Also, we did not stop the CPET assessments by any risk event associated with excessive physiological stress.
We studied two competitive male cyclists recruited from a national cycling club. The inclusion criteria for this study were p.......
There is significant potential in using NIRS wearables as a complementary tool to CPET for evaluating athletic performance and identifying central and peripheral exercise–limiting factors in aerobic or endurance athletes, given that NIRS technology has proven its validity and reliability in assessing microvascular hemodynamics in both cerebral and muscular regions37,38. However, to maximize the benefits of this technology, several considerations must be add.......
We thank all participants in this study and technical laboratory staff for their support in the measurements taken at the Laboratory of Exercise Physiology. The authors FC-B and ME-R were partially supported by the III, IV, and V Research & Innovation Competitions of the School Health Sciences (Faculty of Medicine, Pontificia Universidad Católica de Chile). The author RC-C was funded by Project supported by the Competition for Research Regular Projects, year 2023, code LPR23-17, Universidad Tecnológica Metropolitana.
....Name | Company | Catalog Number | Comments |
Column Scale | SECA | 711 | There are numerous alternatives to this item |
Portable Stadiometer | SECA | 217 | There are numerous alternatives to this item |
12-lead ECG | COSMED | Quark T12x | A 12-lead ECG provides a better understanding of HR during exercise and facilitates the detection of arrhythmias. |
Pulse Oxymeter | COSMED | Integrated pulse oxymeter | |
Ergoespirometer | COSMED | Quark-CPET | Calibration gases and calibration syringe are included |
Cycle-ergometer | Ergoline GmH | ViaSprint 150P | There are numerous alternatives to this item. Must ensure compatibility with provided software |
NIRS weareable | Artinis Medical Systems | Portalite | Articulated NIRS weareable fits the surface where it's placed upon. |
NIRS weareable | Artinis Medical Systems | Portamon | Portamon device provides better results on high adipose-tissue surfaces. |
Metabolic Data Management Software (OMNIA) | COSMED | Software will vary upon system choice | |
NIRS Data Management Software (Oxysoft) | Artinis Medical Systems | Software will vary upon device choice | |
Wireless Probe Type Ultrasound Scanner | SONUS | Duo LC | There are numerous alternatives to this item |
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