Question

Vinnie is a professional road cyclist participating in the 2020 Giro d’Italia, a three-week race nearly 3,600 km in distance with some stages exceeding altitudes of 2,700 m above sea level (i.e., Stelvio Pass, Italy). As the newly hired head of the high-performance team, it is your responsibility to manage his preparation for the event. You must demonstrate to your team a fundamental understanding of physiology, the chronic adaptations expected from his training, and methods that could be implemented to improve the likelihood of success.

Q5)

The longest leg of the race is 228 km, during which energy intake is critical. Glycolysis and β-oxidation are processes that break down carbohydrates (i.e., glucose, sucrose, fructose) and fatty acids, respectively.

1. Individually, what is the total ATP yield from one molecule of glucose and one molecule of palmitate?
2. How did you reach these numbers (i.e., substrate yield and use)?

Based on what you know about the yield and speed of these two pathways, do you recommend Vinnie ingest glucose or fatty acids during the race? (Hint, remember the cross-over concept)

Q6)

During a casual chat with a sport scientist from another team, they suggest preparing “finish bottles” for the longer legs of the race. Along with a dose of painkillers, a “finish bottle” typically contains an ergogenic dose of caffeine (i.e., approximately 3 to 5 mg·kg^-1of bodyweight).

1. As a sympathetic nervous system stimulant, what acute physiological changes will likely occur following caffeine ingestion at these doses?

Additionally, caffeine has a mild effect at mobilising free fatty acids. Please describe what is meant by mobilisation, and how this may influence performance

Answer 1

Palmitic acid is a 16 C compound and will yield 129 ATP molecules up on complete oxidation.

7 cycles of mitochondrial beta oxidation will be undertaken which will yield 7NADH+ 7 FADH2+8 Acetyl CoA

In Krebs cycle each acetyl CoA will yield 3 NADH+ 1 FADH2+ 1 GTP

NADH = 3 ATP

FADH2= 2 ATP

Total ATP produced = 131

Two ATP are used during initial activation of palmitic acid to palmitoyl CoA

So the net ATP produced = 131-2 = 129

B.One molecule ofglucose will produce 36 ATP molecule under aerobic respiration

From Glycolysis = 2 ATP

From Krebs cycle= 2 ATP

From oxidative phosphorylation = 32- 34 ATP

Total it can be considered to be 36 ATP

2.Carbohydrates are the important source of energy for working muscle during the extreme work condition. More exercise, more carb will be used. Moreover in high altitude condition the oxygen level is less and carbohydrates requires only less oxygen for metabolism when compared to fat oxidation. So all the stored glycogen will be fastly metabolised . So the diet of athletes should include more than 60percent of carbohydrate .The athletes should take carbohydrate before, during and after cycling. The energy production from fats will be less under hypoxia condition of high altitude.

3. Caffeine increase sympathetic activity by stimulating the release of catecholamines and inturn leads to tachycardia and increase in blood pressure.

It could enhance physical, and cognitive performance by stimulating CNS. At CNS it acts as adenosine receptor antagonist and stimulate CNS.

4. Caffeine stimulates sympathetic nervous system which inturn cause fatty acid oxidation, lipolysis and energy production that is caffeine will favour fatty acid oxidation.