Aims To investigate the relationship between muscle oxygenation (specifically, the levels of oxygenated haemoglobin and myoglobin [oxyHb/Mb]) during maximal running and muscle fibre composition, and to determine whether muscle fibre composition can be non-invasively estimated from oxyHb/Mb levels during maximal running.
Methods Eight male runners (, 60.9± 4.6 mL·kg−1·min−1) performed an incremental running test on a treadmill. OxyHb/Mb levels of the vastus lateralis during maximal running were measured by near-infrared spectroscopy (NIRS). Muscle fibre composition of the vastus lateralis was determined from muscle biopsy samples from the same region measured by NIRS, and the fibre types were classified as type I, type IIa, or type IIb fibres using traditional pH-sensitive ATPase staining. Type I and type IIa fibres together were defined as oxidative fibres.
Results OxyHb/Mb levels during running were lowest at exhaustion in all participants. OxyHb/Mb levels at exhaustion were positively correlated with the percentages of type I fibres (r=0.755, p<0.05) and oxidative fibres (r=0.944, p<0.01).
Conclusions We conclude that higher oxyHb/Mb levels at exhaustion during maximal running are correlated with a higher percentage of oxidative fibres, indicating the potential importance of oxidative fibres in the maintenance of oxyHb/Mb levels during maximal running. Additionally, muscle fibre composition could be non-invasively estimated from oxyHb/Mb levels during maximal running tests in runners.
- Muscle metabolism
This is an Open Access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Statistics from Altmetric.com
If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.