Deck 5: Exercise Metabolism

Question 1

Energy to run a 40-yard dash comes

A)almost exclusively from the ATP-CP system.
B)exclusively from glycolysis.
C)almost exclusively from aerobic metabolism.
D)from a combination of aerobic/anaerobic metabolism,with most of the ATP being produced aerobically.

Answer 1

A

Question 2

The exercise intensity that promotes the highest amount of total fat oxidation is approximately

A)30% of VO₂ max.
B)60% of VO₂ max.
C)75% of VO₂ max.
D)90% of VO₂ max.

Answer 2

B

Question 3

As exercise intensity increases,there is a progressive increase in the reliance of carbohydrate metabolism in the exercising skeletal muscles.This fact has been described as the

A)substrate shift phenomenon.
B)RQ effect.
C)crossover concept.
D)glycolytic surge.

Answer 3

C

Question 4

The lactate threshold is defined as the work rate or oxygen uptake at which there is a systematic

A)rise in blood levels of lactate dehydrogenase.
B)rise in aerobic metabolism.
C)decrease in blood lactic acid concentration.
D)rise in blood levels of lactic acid.

Question 5

The primary fuel source during prolonged (i.e. ,40-60 minutes),light-intensity (25% VO₂ max)exercise is

A)muscle glycogen.
B)blood glucose.
C)muscle triglycerides.
D)plasma FFA.

Question 6

Energy to run a maximal 400-meter race (i.e. ,50 to 60 seconds)comes from

A)aerobic metabolism exclusively.
B)mostly aerobic metabolism with some anaerobic metabolism.
C)a combination of aerobic/anaerobic metabolism,with most of the ATP coming from anaerobic sources.
D)the ATP-CP system exclusively.

Question 7

The slow rise in oxygen consumption over time during submaximal,prolonged exercise in a hot environment is likely due to

A)high blood levels of lactic acid.
B)rising body temperature.
C)rising blood levels of insulin.
D)a decrease in blood glucose levels.

Question 8

After the first few minutes of constant-load,submaximal exercise,VO₂ reaches steady state,indicating that

A)the ATP demand is being met aerobically.
B)levels of lactic acid in the blood are very high.
C)the exercise can be continued indefinitely without fatigue.
D)the oxygen uptake is not sufficient to meet the ATP demand.

Question 9

Which of the following factors are possible mechanisms to explain the lactate threshold?

A)low muscle oxygen
B)recruitment of fast-twitch muscle fibers
C)reduced rate of lactate removal from the blood
D)All of the above answers are correct

Question 10

The first bioenergetic pathway to become active in skeletal muscle at the onset of exercise is

A)glycolysis.
B)the ATP-CP system.
C)the Krebs cycle.
D)the electron transport chain.

Question 11

The energy to perform long-term exercise (i.e. ,>30 minutes)comes primarily from

A)aerobic metabolism.
B)a combination of aerobic/anaerobic metabolism,with anaerobic metabolism producing the bulk of the ATP.
C)anaerobic metabolism.
D)anaerobic metabolism,with the ATP-PC system producing the bulk of the ATP.

Question 12

A respiratory quotient (RQ)of 0.95 during steady-state exercise is suggestive of a(n)

A)high rate of carbohydrate metabolism.
B)high rate of fat metabolism.
C)equal rate of fat/carbohydrate metabolism.
D)high rate of protein metabolism

Question 13

During the "rapid" portion of the oxygen debt (or EPOC),the excess VO₂ is due to

A)high body temperature.
B)gluconeogenesis.
C)restoration of muscle CP and replacement of blood and muscle oxygen stores.
D)elevated blood levels of epinephrine and norepinephrine.

Question 14

The primary fuel source during high-intensity (85% VO₂ max)exercise is

A)muscle glycogen.
B)blood glucose.
C)muscle triglycerides.
D)plasma FFA.

Question 15

The drift upward of VO₂ during constant-load exercise in a hot environment is due to

A)rising blood levels of lactate.
B)decreasing blood levels of hormones.
C)increasing body temperature.
D)decreasing body temperature.

Question 16

Most of the carbohydrate (e.g. ,for a rested,well-fed athlete)used as a substrate during high-intensity exercise comes from

A)muscle glycogen stores.
B)blood glucose.
C)liver glycogen stores.
D)glycogen stored in fat cells

Question 17

Any factor that increases the amino acid pool in the muscle can enhance protein metabolism in the exercising muscle.Which of the following factors can increase the amino acid pool in the muscle?

A)short-duration (i.e. ,1-3 minutes)high intensity exercise.
B)prolonged exercise (> 2 hours).
C)high levels of lactate in the blood.
D)None of the above answers are correct.

Question 18

The term oxygen deficit refers to the

A)lag in oxygen consumption at the beginning of exercise.
B)excess oxygen consumption during recovery from exercise.
C)amount of oxygen required to maintain a steady state during constant-load exercise.
D)amount of oxygen utilized by the brain in the first few minutes of exercise.

Question 19

The process of breaking down triglycerides into free fatty acids and glycerol is called

A)beta oxidation.
B)glycogenolysis.
C)lipolysis.
D)lipogenesis.

Question 20

Exercise trained individuals have a lower oxygen deficit;this may be due to

A)increased pulmonary lung capacity.
B)increased levels of glycolytic enzymes in the trained muscle.
C)a greater involvement of the ATP-CP energy system at the onset of exercise.
D)having a better developed aerobic bioenergetic capacity.

Question 21

During steady-state exercise,an RQ of 0.73 would indicate

A)a high level of fat metabolism.
B)a high level of carbohydrate metabolism.
C)a high level of protein metabolism.
D)None of the answers above are correct

Question 22

Which of the following factors could explain the rise in blood lactic acid at the lactate threshold?

A)an increased rate of lactate production
B)a decreased rate of removal of lactic acid from the blood
C)both A and B are correct
D)none of the above answers are correct.

Question 23

Which of the following would NOT increase (whole body)oxygen consumption during recovery from exercise and increase excess post-exercise oxygen consumption (EPOC)?

A)high intensity of exercise
B)elevated body temperature above normal
C)high blood levels of hormones (i.e. ,epinephrine)
D)None of the above answers are true

Question 24

Lactate is formed and accumulates in the muscle when the rate of glycolytic production of NADH exceeds the rate at which these products are shuttled into the mitochondria.

Question 25

The respiratory exchange ratio is often referred to as the respiratory quotient during steady-state exercise.

Question 26

Which of the following is true of the Cori cycle?

A)This cycle can decrease blood lactate concentration by liver removal of lactate from the blood and converting this lactate into glucose.
B)This cycle plays a key role in gluconeogenesis in skeletal muscle.
C)This cycle coverts glycogen into lactate in the liver.
D)This cycle is responsible for converting amino acids into glucose.

Question 27

Exercise trained individuals usually produce less lactate than untrained individuals during the transition from rest to steady-state exercise.

Question 28

When using the RQ to estimate fuel usage during exercise,the role that protein plays as a fuel source is often ignored.Why?

A)because protein generally plays a relatively small role as a fuel source during exercise
B)because protein cannot be used a fuel in skeletal muscle
C)because protein is only used as a fuel in muscle during short duration exercise lasting less than 20 seconds.
D)none of the above answers are correct.

Question 29

Depletion of muscle carbohydrate stores during exercise can decrease the ability of the muscle to metabolize fat by

A)decreasing the rate of muscle lactic acid production.
B)reducing the concentrations of citric acid cycle intermediates.
C)increasing the rate of protein metabolism.
D)reducing the rate of protein metabolism.

Question 30

Lactate accumulation during exercise is a major cause of the muscle soreness that occurs 24-48 hours after exercising.
41.The exercise intensity at which blood lactate levels reach four millimoles per liter is often termed the onset of blood lactate accumulation (OBLA).

Question 31

The carbohydrate fuel source that becomes most important after 3-4 hours of moderate-intensity (~70% VO₂ max)exercise is

A)muscle glycogen.
B)blood glucose.
C)muscle triglycerides.
D)plasma FFA.

Question 32

Fat oxidation requires more oxygen than carbohydrate oxidation because carbohydrates contain LESS oxygen than fats.

Question 33

VO₂ max is determined by

A)the maximum ability of the cardiorespiratory system to deliver oxygen to the muscle.
B)the ability of the muscle to take up and use oxygen to produce ATP.
C)both A and B are correct.
D)none of the above answers are correct.

Question 34

The RER can rise above 1.00

A)during high-intensity exercise.
B)if VCO₂ > VO₂.
C)when the buffering of lactic acid stimulates ventilation to eliminate CO₂.
D)when all of these occur.