Near Infrared Spectroscopy (NIRS) is a non-invasive technique which can be used to monitor changes in oxygen saturation and haemoglobin concentration in the muscle microvasculature during exercise. The recent development of reliable portable NIRS devices presents the opportunity to measure muscle oxygenation and blood flow in-vivo during simulated competition in a realistic sporting setting. Therefore, portable NIRS was used to monitor right and left leg quadriceps oxygenation and blood volume changes during simulated competition in short-track speed skating, across a range of race distances. During race simulation over 500m in male subjects, linear regression analysis revealed asymmetry between right and left vastus lateralis muscle oxygen saturation (TSI%) data: TSI% decreased to a plateau after 8s, after which right leg TSI% remained constant throughout the rest of the simulation (slope value = 0.01), whereas left leg TSI% increased steadily (slope value = 0.16), leading to a significant asymmetry (p<0.05) in the final lap. Although total muscle haemoglobin concentration decreased equally in both legs at the start of the simulation, during the course of subsequent laps there was a strong asymmetry during cornering; when skaters travelled solely on the right leg there was a decrease in its haemoglobin concentration whereas an increase was seen in the left leg. This difference was attributed to the differing technical demands placed on the two legs during cornering at high speeds. When comparisons were made between NIRS-derived changes over 3 race distances in males and females, it was shown that neither race distance nor sex had a significant effect on the magnitude of maximal muscle desaturation (~TSlmax). Linear regression analysis revealed asymmetry between right and left leg desaturation in males during the final stages of skating across each race distance, but not in females. Thus, NIRS-derived measurements of local muscle oxygenation can provide insight into velocity and pacing changes in speed skating, and technical differences between male and female skaters. Comparison between skating and cycling data revealed that NIRS-detected leg asymmetry was due to the specific demands of short-track speed skating. However, heterogeneity between individuals is not specific to the mode of exercise. Finally, the possibility of using portable NIRS to monitor adaptations to endurance training in . . elite biathletes was examined. Training did not significantly affect muscle oxygen saturation levels during submaximal treadmill running, although it did reduce blood lactate values. Comparison of data for males and females revealed a significant effect of adipose tissue thickness on magnitude of tissue saturation change during running. The results presented here suggest that the utility ofNIRS as a tool for monitoring peripheral adaptations to training interventions in elite athletes is still subject to debate. However, this thesis does show that portable NIRS can be used in a variety of sporting contexts as a viable tool to address questions relating to the supply and utilisation of oxygen in specific muscles during dynamic exercise in the field.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:573739 |
| Date | January 2012 |
| Creators | Hesford, Catherine Mary |
| Publisher | University of Essex |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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