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

1)Your first job was to schedule a VO₂max test forVinnie to examine his aerobic fitness. After repeating theassessment several weeks later after an intensive training block,you notice that VO₂max has dropped, but there has beenan increase in VT₂. Please discuss why VO₂maxdecreased and what impact both changes will have onperformance?

2)Out of interest, you decide to measure Vinnie’s grossmechanical efficiency during cycling (i.e., the ratio of workaccomplished to energy expended). You determine that he is 21.9%efficient. Please explain what efficiency is a measure of, wheredoes this value sit within normal efficiency data and why you areunlikely to see values much higher (e.g., 50%)?

3)Within the alveoli, the partial pressure of O₂ isreduced from that measured in the outside air (160 mmHg) toapproximately 105 mmHg.

1. What three factors contribute to this reduction inP_AO₂?

What values do you expect to observe in PO₂ andP_AO₂ when Vinnie is cycling at the peak ofStelvio Pass (barometric pressure = 543 mmHg)?

What impact would the change in P_AO₂ haveon Vinnie’s performance?

4)

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

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

Based on what you know about the yield and speed of these twopathways, do you recommend Vinnie ingest glucose or fatty acidsduring the race? (Hint, remember the cross-overconcept)

5)

You recommend that Vinnie performs altitude training as part ofhis preparation for the race, a training approach that is novel tohim.

1. What physiological changes would you expect in the short (i.e.,acute), and long-term (i.e., chronic)?
2. How will the physiological changes influence performance in theshort (i.e., acute), and long-term (i.e., chronic)?

6)

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

1. As a sympathetic nervous system stimulant, what acutephysiological changes will likely occur following caffeineingestion at these doses?

Additionally, caffeine has a mild effect at mobilising freefatty acids. Please describe what is meant by mobilisation, and howthis may influence performance

7)

Given that the average distance of each leg is 170.5 km indistance, and sometimes undulating in elevation, you understandthat fatigue is inevitable. The energy depletion model of fatiguefocuses around the concept that depleted substrates are just onesource of fatigue, particularly observed in muscle glycogen andphosphocreatine stores.

1. As an aerobic event, why do you expect depletion in glycogenand phosphocreatine?
2. Why, specifically, is it crucial to replenish muscle glycogenstores prior to the next leg?

8)

As the event is soon approaching, parts of Hungary areexperiencing a heatwave. Indeed, temperatures may exceed 32°Celsius during the first leg of the race leaving Budapest.

1. Will the ambient temperature have any impact on Vinnie’sperformance?

In terms of thermoregulation, what physiological changes arelikely to occur during this leg of the race?