Interrelationships between Mitochondrial Function, Maximal Oxygen Consumption, Running Economy, and Diet in Elite Male and Female Runners
The relationships between maximal oxygen consumption (VO2max), mitochondrial function and running economy were investigated in a population of twenty-one endurance trained males and females (range=18-54 yrs). The purposes of this study were: 1) to determine whether mitochondrial oxidative capacity, as defined by the maximal activities of citrate synthase (CS), cytochrome c oxidase (COX), and beta-hydroxyacyl-CoA dehydrogenase (BHAD), is a significant determinant of maximal oxygen consumption in endurance trained men and women, and 2) to observe the relationship between maximal oxygen uptake and running economy in the same population. Muscle biopsy samples were taken from the vastus lateralis prior to a 90-minute bout of submaximal running (65% VO2max) from which running economy was assessed. Running economy was observed to significantly negatively correlate with VO2max, expressed in either absolute or relative values: L/min (r = -.506), ml/kg body mass/min (r = -.703) and ml/kg FFM/min (r = -.700). Data also show that maximal COX activity was significantly related to VO2max, L/min (r = .789). In addition, non-significant positive correlations were apparent between both CS and COX activity and all other expressions of VO2max (r > .6). BHAD activity was not related to any measured variable. These results confirm that an inverse relationship is present relating VO2max and running economy. Also, data herein indicate that maximal activities of key marker enzymes of the citric acid cycle and oxidative phosphorylation are likely a significant factor determining whole-body maximal oxygen consumption in endurance trained males and females.
Advisor:Dennis Landin; Robert Wood; Arnold Nelson
School:Louisiana State University in Shreveport
School Location:USA - Louisiana
Source Type:Master's Thesis
Date of Publication:03/31/2006