Chapter 4

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

A.

Carbohydrate used as a fuel source during exercise comes from both blood glucose and muscle glycogen. The relative contribution of these two sources of carbohydrate varies as a function of A. both exercise intensity and exercise duration are correct. B. exercise duration. C. None of these is true. D. exercise intensity.

A.

During the "rapid" portion of the excess post-exercise oxygen consumption (EPOC), the excess VO2 is due to A. restoration of muscle CP and replacement of blood and muscle oxygen stores. B. elevated blood levels of epinephrine and norepinephrine. C. gluconeogenesis. D. high body temperature.

A.

Energy to run a maximal 400-meter race (i.e., 50 to 60 seconds) comes from A. a combination of aerobic/anaerobic metabolism, with most of the ATP coming from anaerobic sources. B. the ATP-CP system exclusively. C. aerobic metabolism exclusively. D. mostly aerobic metabolism with some anaerobic metabolism.

A.

In general, very heavy exercise lasting 60 seconds utilizes energy production that is A. 70% anaerobic/30% aerobic. B. 40% anaerobic/60% aerobic. C. 30% anaerobic/70% aerobic. D. 50% anaerobic/50% aerobic.

A.

The RER can rise above 1.00 A. All of these answers are correct. B. if VCO2 > VO2. C. when the buffering of lactic acid stimulates ventilation to eliminate CO2. D. during high-intensity exercise.

A.

VO2 max is determined by A. both the maximum ability of the cardiorespiratory system to deliver oxygen to the muscle and the ability of the muscle to take up and use oxygen to produce ATP are correct. B. the maximum ability of the cardiorespiratory system to deliver oxygen to the muscle. C. None of these answers is correct. D. the ability of the muscle to take up and use oxygen to produce ATP.

A.

Which of the following factors are possible mechanisms to explain the lactate threshold? A. All of these answers are correct B. Recruitment of fast-twitch muscle fibers C. Reduced rate of lactate removal from the blood D. Accelerated rate of glycolysis due to epinephrine

A.

Which of the following factors causes the shift from fat to carbohydrate metabolism as exercise intensity increases during a graded exercise test? A. Increase in the circulating levels of epinephrine B. Decrease in protein availability within the muscle C. All of these are true D. Increase in the recruitment of fast muscle fibers

A.

Which of the following would NOT increase (whole body) oxygen consumption during recovery from exercise and increase excess post-exercise oxygen consumption (EPOC)? A. None of these answers is true B. Elevated body temperature above normal C. High blood levels of hormones (i.e., epinephrine) D. High intensity of exercise

A.

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

B.

The energy to perform long-term submaximal exercise (i.e., >30 minutes) comes primarily from A. a combination of aerobic/anaerobic metabolism, with anaerobic metabolism producing the bulk of the ATP. B. aerobic metabolism. C. anaerobic metabolism. D. anaerobic metabolism, with the ATP-PC system producing the bulk of the ATP.

B.

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 blood levels of lactic acid. C. rise in aerobic metabolism. D. decrease in blood lactic acid concentration.

B.

The measurement of VO2 max is commonly performed during a graded exercise test on a treadmill. However, some subjects will voluntarily terminate an incremental exercise test without reaching VO2 max. The primary (gold standard) criteria to determine if a subject reached their "true" VO2 max during an exercise test is: A. A respiratory exchange ratio >1.15 B. A plateau in oxygen uptake with an increase in work rate C. A max heart rate within 20 beats of age-predicted max heart rate D. A blood lactate level exceeding 8 times resting levels

B.

The primary fuel source during high-intensity (85% VO2 max) exercise is A. blood glucose. B. muscle glycogen. C. muscle triglycerides. D. plasma FFA.

B.

The process of breaking down triglycerides into free fatty acids and glycerol is called A. glycogenolysis. B. lipolysis. C. beta oxidation. D. lipogenesis

B.

After the first few minutes of constant-load, submaximal exercise, VO2 reaches steady state, indicating that A. the oxygen uptake is not sufficient to meet the ATP demand. B. levels of lactic acid in the blood are very high. C. the ATP demand is being met aerobically. D. the exercise can be continued indefinitely without fatigue.

C.

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. High levels of lactate in the blood. B. None of these answers is correct. C. Prolonged exercise (>2 hours). D. Short-duration (i.e., 1-3 minutes) high intensity exercise.

C.

Depletion of muscle carbohydrate stores during exercise can decrease the ability of the muscle to metabolize fat by A. increasing the rate of protein metabolism. B. reducing the rate of protein metabolism. C. reducing the concentrations of citric acid cycle intermediates. D. decreasing the rate of muscle lactic acid production.

C.

During steady-state exercise, an RQ of 0.73 would indicate A. a relatively high level of protein metabolism. B. a relatively high level of carbohydrate metabolism. C. a relatively high level of fat metabolism. D. None of these answers is correct.

C.

One of the mechanism(s) responsible for activation of proteases during long-duration exercise is A. a rise in blood lactate levels. B. None of these is true. C. an increase in cytosolic calcium levels in the muscle. D. a rise in muscle temperature.

C.

The carbohydrate fuel source that becomes most important after 3 hours of moderate-intensity (~50% VO2 max) exercise is A. plasma FFA. B. muscle triglycerides. C. blood glucose. D. muscle glycogen.

C.

The exercise intensity that promotes the highest amount of total fat oxidation is approximately A. 90% of VO2 max. B. 30% of VO2 max. C. 60% of VO2 max. D. 75% of VO2 max.

C.

The slow rise in oxygen consumption over time during prolonged exercise (at a constant sub-maximal load) in a hot environment is due, in part, to A. a decrease in blood glucose levels. B. rising blood levels of insulin. C. rising blood levels of epinephrine and norepinephrine. D. high blood levels of lactic acid.

C.

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

C.

When using the RQ to estimate fuel usage during exercise, the role that protein plays as a fuel source is often ignored. Why? A. None of these answers is correct. B. because protein is only used as a fuel in muscle during short duration exercise lasting less than 20 seconds. C. because protein generally plays a relatively small role as a fuel source during exercise. D. because protein cannot be used a fuel in skeletal muscle.

C.

Which of the following exercise intensities would rely primarily on carbohydrate as a fuel source? A. 55% of VO2 max. B. 40% of VO2 max. C. 90% of VO2 max. D. 30% of VO2 max.

C.

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 an increased rate of lactate production and a decreased rate of removal of lactic acid from the blood are correct D. None of these answers is correct

C.

Which of the following is true about VO2 during exercise? A. None of these is true. B. VO2 is an indicator of glycolytic ATP production. C. VO2 increases linearly with work rate. D. VO2 drops sharply just prior to fatigue.

C.

Which of the following is true concerning VO2 max? A. It is the maximal volume of oxygen that can be moved into the lungs in one minute. B. It is the highest VO2 achieved during prolonged steady-state exercise. C. It is a valid measure of cardiovascular fitness. D. It occurs at a lower intensity of exercise than the lactate threshold.

C.

At rest, the O2 consumption of a 70-kg young adult is approximately A. 250 ml/min. B. 3.5 ml/kg/min. C. 0.25 L/min. D. All of these answers are correct.

D.

Energy to run a 40-yard dash comes A. exclusively from glycolysis. B. from a combination of aerobic/anaerobic metabolism, with most of the ATP being produced aerobically. C. almost exclusively from aerobic metabolism. D. almost exclusively from the ATP-CP system.

D.

Exercise trained individuals have a lower oxygen deficit; this may be due to A. a greater involvement of the ATP-CP energy system at the onset of exercise. B. increased levels of glycolytic enzymes in the trained muscle. C. increased pulmonary lung capacity. D. having a better developed aerobic bioenergetic capacity.

D.

Most of the carbohydrate (e.g., for a rested, well-fed athlete) used as a substrate during high-intensity exercise comes from A. liver glycogen stores. B. glycogen stored in fat cells. C. blood glucose. D. muscle glycogen stores.

D.

Removal of lactic acid following a bout of intense exercise is A. the same whether the subject rests or performs light exercise (~30% VO2 max). B. more rapid if the subject rests, compared to performing light exercise. C. more rapid if the subject performs heavy exercise (>70% VO2 max), compared to rest. D. more rapid if the subject performs light exercise (~30% VO2 max), compared to rest.

D.

The bioenergetic pathway that first provides ATP for skeletal muscle at the onset of exercise is A. the electron transport chain. B. glycolysis. C. the Krebs cycle. D. the ATP-CP system.

D.

The oxygen debt is generally higher following heavy exercise when compared with light exercise because heavy exercise A. produces more lactic acid. B. is of shorter duration than light exercise. C. results in a greater level of liver glycogen depletion. D. results in greater body heat gained, greater CP depleted, higher blood levels of epinephrine and norepinephrine, and higher blood lactate levels.

D.

The primary fuel source during prolonged (i.e., >120 minutes), light-intensity (40% VO2 max) exercise is A. muscle triglycerides. B. muscle glycogen. C. blood glucose. D. plasma FFA.

D.

Which of the following is true of the Cori cycle? A. This cycle plays a role as part of the lactate shuttle. B. This cycle coverts lactate into glucose in the liver. C. This cycle can decrease blood lactate concentration by liver removal of lactate from the blood and converting this lactate into glucose. D. All of these are true

D.