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

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)?

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?

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.

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?

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

Accepted Answer

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

Question 10

Fatigue refers to

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

ATP concentrations in muscles are maintained relatively constant even during exercise, as ATP is rapidly regenerated through metabolic pathways like glycolysis and oxidative phosphorylation.

Question 12

When the intensity of exercise exceeds 75% of VO₂ max, which of the following fibers is brought into play?

Accepted Answer

Type IIx fibers are recruited when intensity of exercise exceeds 75% of VO₂ max.

Question 13

In aerobic performances lasting 3 to 20 minutes, which of the following factors limits performance?

Accepted Answer

Aerobic performances lasting 3-20 minutes rely heavily on carbohydrate as an energy source. The availability of carbohydrate supplementation during the performance will therefore greatly affect the athlete's ability to maintain the necessary energy levels.

Question 14

Free radicals may promote muscle fatigue by

Accepted Answer

Free radicals can damage contractile proteins, such as actin and myosin, which are essential for muscle contraction. This can limit the number of cross-bridges formed between actin and myosin, reducing the force generated during muscle contraction and promoting muscle fatigue.

Question 15

Reaction time and skill would be most important for

Accepted Answer

Reaction time and skill are most important for a sprinter competing in the 100-m dash, as they need to have explosive speed and a fast reaction time to successfully complete the race in a short amount of time. While reaction time and skill may also be important for marathon and cross-country runners, their success is more reliant on endurance and pacing rather than speed and quick reactions.

Question 16

Having a high VO₂ max would be a primary factor for success in performances lasting

Accepted Answer

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

Question 17

Blood buffers would most likely improve performances lasting

Accepted Answer

Blood buffers are most effective in improving performance in events lasting 30 to 180 seconds because they help to delay the onset of fatigue by neutralizing the increase in acidity (from lactic acid) in the muscles during high-intensity, anaerobic activities.

Question 18

Which of the following has been shown to interfere with cross-bridge "cycling" during exercise?

Accepted Answer

H⁺ refers to inorganic phosphate (Pi) bound to the myosin head and actin filament, respectively, during muscle contraction. Accumulation of Pi is known to interfere with cross-bridge cycling during exercise, making option B the correct choice. The other options, such as accumulation of ATP or decrease in Pi, do not interfere with cross-bridge cycling during exercise. A decrease in Na⁺ has no known effect on cross-bridge cycling.

Quiz 19: Factors Affecting Performance

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

A high H⁺ concentration can contribute to fatigue by

What is the primary energy source in ultra short-term performances (less than 10 seconds) ?

In short-term performances (10-180 seconds) which of the following factors is the primary cause of fatigue?

At three minutes of all-out exercise, __________ of the ATP is derived from aerobic sources.

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

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?

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

Carbohydrate supplementation during exercise is most important in performances lasting

Fatigue refers to

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

When the intensity of exercise exceeds 75% of VO₂ max, which of the following fibers is brought into play?

In aerobic performances lasting 3 to 20 minutes, which of the following factors limits performance?

Free radicals may promote muscle fatigue by

Reaction time and skill would be most important for

Having a high VO₂ max would be a primary factor for success in performances lasting

Blood buffers would most likely improve performances lasting

Which of the following has been shown to interfere with cross-bridge "cycling" during exercise?

Quiz 19: Factors Affecting Performance

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

A high H+ concentration can contribute to fatigue by

What is the primary energy source in ultra short-term performances (less than 10 seconds) ?

In short-term performances (10-180 seconds) which of the following factors is the primary cause of fatigue?

At three minutes of all-out exercise, __________ of the ATP is derived from aerobic sources.

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

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?

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

Carbohydrate supplementation during exercise is most important in performances lasting

Fatigue refers to

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

When the intensity of exercise exceeds 75% of VO2 max, which of the following fibers is brought into play?

In aerobic performances lasting 3 to 20 minutes, which of the following factors limits performance?

Free radicals may promote muscle fatigue by

Reaction time and skill would be most important for

Having a high VO2 max would be a primary factor for success in performances lasting

Blood buffers would most likely improve performances lasting

Which of the following has been shown to interfere with cross-bridge "cycling" during exercise?

A high H⁺ concentration can contribute to fatigue by

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

When the intensity of exercise exceeds 75% of VO₂ max, which of the following fibers is brought into play?

Having a high VO₂ max would be a primary factor for success in performances lasting