CSSD Exercise Physiology & Energy Metabolism 3

Question 1

Respiratory exchange ratio (RER) values approaching 1.0 during steady-state exercise indicate:

Accepted Answer

Predominant carbohydrate oxidation

Answer

An RER of 1.0 indicates that carbohydrate is the primary fuel because the molar ratio of CO2 produced to O2 consumed equals 1.0 for glucose oxidation.

Question 2

What physiological mechanism primarily explains the ergogenic effect of sodium bicarbonate supplementation during high-intensity exercise?

Accepted Answer

Extracellular buffering of hydrogen ions, delaying acidosis

Answer

Sodium bicarbonate increases extracellular bicarbonate, creating a larger gradient for hydrogen ion efflux from muscle cells, thereby delaying intracellular acidosis and fatigue.

Question 3

Which of the following BEST describes the Cori cycle?

Accepted Answer

Transport of lactate from muscle to the liver, where it is converted to glucose via gluconeogenesis

Answer

The Cori cycle shuttles lactate produced by muscle to the liver, where it is converted back to glucose through gluconeogenesis and released into circulation.

Question 4

An endurance-trained athlete has a higher maximal fat oxidation rate than an untrained individual primarily because of:

Accepted Answer

Greater mitochondrial density and upregulated oxidative enzyme activity

Answer

Training-induced mitochondrial biogenesis and upregulation of enzymes such as citrate synthase and β-HAD increase the capacity for aerobic fat oxidation.

Question 5

During a Wingate anaerobic power test, the primary energy system used in the first 10 seconds is:

Accepted Answer

Phosphocreatine (PCr) system

Answer

The phosphocreatine system provides rapid ATP resynthesis in the first ~10 seconds of maximal effort before glycolysis becomes the dominant pathway.

(CSSD) Board Certified Specialist in Sports Dietetics Practice Test

(CSSD) Board Certified Specialist in Sports Dietetics Practice Test

CSSD Exercise Physiology & Energy Metabolism 3