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Unformatted text preview: ent of FG vs. FOG vs. SO fibers Capacity to shuttle NADH to mitochondria Build-up of NADH in cytoplasm: ↑ fast glycolysis Lactate Threshold
= Lactate entry (production) >> Lactate removal (oxidation)
◦ The inflection point that suggests the shift towards
predominantly fast glycolytic ATP synthesis Progressive ↑ in lactate prior to LT, exponential ↑
in lactate @ LT
◦ ~50% VO2max untrained ◦ ~75% VO2max trained Lactate
• Training= Delayed shift from oxidative to nonoxidative mechanisms
◦ greater oxidative capacity Greater efficiency of lactate shuttles (“lactate consumer”) Exercise Intensity & Fuel
As exercise intensity increases there is greater
reliance on CHO and reduced reliance on FAT
◦ ↑ blood epinephrine levels ◦ SO → FOG → FG fiber recruitment Oxidative → Non-oxidative pathways ↓ O2 availability ↓ opportunity for oxidative mechanisms Exercise Intensity & Fuel
Selection Respiratory exchange ratio (RER)
◦ = VCO2/VO2 ◦ 1.0= CHO ◦ 0.7= FAT RER RER
> 1.0 w/ high intensity, NON- steady state exercise H+ from HLA, ↑ NADH + H+ production (↑ATP use) Bicarbonate buffering system: Expired at lungs=
↑CO2 part of RER
VCO2/ VO2 Fuel for Exercise
During short duration, graded exercise, CHO
use ↑ & FAT use ↓ as...
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This document was uploaded on 03/26/2014.
- Spring '14