Deck 19: Factors Affecting Performance

Question 1

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

Answer 1

True

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.

Answer 2

D

Question 3

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

A) muscle glycogen
B) phosphocreatine
C) blood glucose
D) plasma FFA

Answer 3

B

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

Question 5

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

A) 10%
B) 40%
C) 60%
D) 90%

Question 6

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

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

Question 8

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

Question 9

Carbohydrate supplementation during exercise is most important in performances lasting

A) less than 10 seconds.
B) 30 to 180 seconds.
C) 3 to 20 minutes.
D) longer than 20 minutes.

Question 10

Fatigue refers to

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

Question 11

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

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

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

Question 14

Free radicals may promote muscle fatigue by

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

Question 15

Reaction time and skill would be most important for

A) a marathon runner.
B) a cross-country runner.
C) a sprinter competing in the 100-m dash.
D) all of the above.

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.

Question 17

Blood buffers would most likely improve performances lasting

A) less than 10 seconds.
B) 30 to 180 seconds.
C) 3 to 20 minutes.
D) longer than 20 minutes.

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)