Question 1

Fatigue can be viewed as an imbalance between ATP requirements and ATP production.

Accepted Answer

ATP (adenosine triphosphate) is the molecule used by cells as a primary source of energy. When the demands for energy (ATP requirements) exceed the body's ability to produce ATP, fatigue can occur. This can happen during prolonged physical activity or due to other factors such as illness or lack of sleep. Therefore, fatigue can be viewed as an imbalance between ATP requirements and ATP production.

Question 2

A high H⁺ concentration can contribute to fatigue by A) reducing the force per cross-bridge. B) interfering with Ca⁺⁺ binding to troponin. C) inhibiting Ca⁺⁺ from the sarcoplasmic reticulum. D) all of the above.

Accepted Answer

A high concentration of H⁺ can contribute to fatigue by reducing the force per cross-bridge, interfering with Ca⁺⁺ binding to troponin, and inhibiting Ca⁺⁺ release from the sarcoplasmic reticulum. All of these factors can impair muscle contraction and lead to fatigue.

Question 3

What is the primary energy source in ultra short-term performances (less than 10 seconds)?&#10;A) muscle glycogen&#10;B) phosphocreatine&#10;C) blood glucose&#10;D) plasma FFA

Accepted Answer

Phosphocreatine is the primary energy source in ultra short-term performances (less than 10 seconds). It can rapidly regenerate ATP which is necessary for muscle contraction during the activity.

Question 4

In short-term performances (10-180 seconds) which of the following factors is the primary cause of fatigue? A) muscle glycogen depletion B) depressed plasma FFA C) hypoglycemia D) H⁺ accumulation

Accepted Answer

During short-term performances, the primary cause of fatigue is the accumulation of hydrogen ions (H+), inorganic phosphate (Pi), and potassium ions (K+) which results in the decrease of pH in the muscle, leading to an interference in the actomyosin interaction and, as a consequence, a reduction in force production. This is represented by the acronym H⁺. Muscle glycogen depletion, depressed plasma FFA, and hypoglycemia have more impact on long-term performances.

Question 5

At three minutes of all-out exercise, __________ of the ATP is derived from aerobic sources.&#10;A) 10%&#10;B) 40%&#10;C) 60%&#10;D) 90%

Accepted Answer

At three minutes of all-out exercise, approximately 60% of the ATP is derived from aerobic sources as the body starts to rely more on aerobic metabolism after the initial anaerobic energy burst.

Question 6

Running economy becomes an increasingly important determinant of success as the duration of the performance increases.

Accepted Answer

Running economy refers to the efficiency of an athlete's energy utilization while running. As the duration of a performance increases, the athlete's energy utilization becomes increasingly important, making running economy a crucial determinant of success.

Question 7

A subject, with eyes closed, repeatedly contracts a muscle until fatigue occurs. When the eyes are opened, tension is restored. This experiment is a demonstration of fatigue being related to which of the following sites?

A) muscle
B) central nervous system
C) mitochondria
D) peripheral nervous system

Accepted Answer

The fact that tension is restored when the eyes are opened suggests that the fatigue is not due to a problem with the muscle or mitochondria, but rather is centrally mediated. Therefore, the best choice is B, central nervous system.

Question 8

Running performances lasting 21 to 60 minutes are conducted at an energy expenditure equal to VO₂ max.

Accepted Answer

Running performances lasting 21 to 60 minutes are typically conducted at an energy expenditure below VO₂ max, as maintaining VO₂ max for such durations is physiologically challenging.

Question 9

Carbohydrate supplementation during exercise is most important in performances lasting&#10;A) less than 10 seconds.&#10;B) 30 to 180 seconds.&#10;C) 3 to 20 minutes.&#10;D) longer than 20 minutes.

Accepted Answer

The answer of Carbohydrate supplementation during exercise is most important...

Question 10

Fatigue refers to&#10;A) the sensation of pain associated with repeated muscle contractions.&#10;B) an inability to maintain power output during repeated contractions.&#10;C) the feeling of sleepiness that occurs during repeated muscle contractions.&#10;D) an increased free radical production that occurs during repeated muscle contractions.

Accepted Answer

Fatigue refers to the inability to maintain power output during repeated contractions. A is incorrect because pain is not a defining characteristic of fatigue. C is incorrect because sleepiness is not necessarily associated with fatigue, and D is incorrect because while free radical production can contribute to fatigue, it is not the defining characteristic of fatigue.

Question 11

During exercise, muscle ATP concentrations often fall to less than half of resting levels.

Accepted Answer

The answer of During exercise, muscle ATP concentrations often fall...

Question 12

When the intensity of exercise exceeds 75% of VO₂ max, which of the following fibers is brought into play? A) Type I B) Type IIa C) Type IIx D) Type Ix

Accepted Answer

The answer of When the intensity of exercise exceeds 75%...

Question 13

In aerobic performances lasting 3 to 20 minutes, which of the following factors limits performance? A) VO₂ max B) creatine phosphate depletion C) availability of carbohydrate supplementation D) availability of plasma FFA

Accepted Answer

The answer of In aerobic performances lasting 3 to 20...

Question 14

Free radicals may promote muscle fatigue by&#10;A) damaging contractile proteins and limiting the number of cross-bridges.&#10;B) blocking action potential transmission across the neuromuscular junction.&#10;C) reducing ATP production.&#10;D) none of the above; free radicals do not promote muscle fatigue.

Accepted Answer

The answer of Free radicals may promote muscle fatigue by&#10;A)...

Question 15

Reaction time and skill would be most important for&#10;A) a marathon runner.&#10;B) a cross-country runner.&#10;C) a sprinter competing in the 100-m dash.&#10;D) all of the above.

Accepted Answer

The answer of Reaction time and skill would be most...

Question 16

Having a high VO₂ max would be a primary factor for success in performances lasting A) less than 10 seconds. B) 30 to 180 seconds. C) 3 to 20 minutes. D) all of the above.

Accepted Answer

The answer of Having a high VO₂ max would be...

Question 17

Blood buffers would most likely improve performances lasting&#10;A) less than 10 seconds.&#10;B) 30 to 180 seconds.&#10;C) 3 to 20 minutes.&#10;D) longer than 20 minutes.

Accepted Answer

The answer of Blood buffers would most likely improve performances...

Question 18

Which of the following has been shown to interfere with cross-bridge "cycling" during exercise? A) an accumulation of ATP B) an accumulation of H⁺ C) a decrease in Na⁺ D) a decrease in Pi (inorganic phosphate)

Accepted Answer

The answer of Which of the following has been shown...

Deck 19: Factors Affecting Performance