Chapter 6 Fatigue

Question 1

What is fatigue?

Answer 1

The inability to maintain the required power output to continue muscular work at a given intensity.

Question 2

What is the cause of fatigue in the ATP-PCR system?

Answer 2

The depletion of PCR.

Question 3

What are the two causes of fatigue in Glycolysis?

Answer 3

Hydrogen accumulation and Inorganic phosphate accumulation.

Question 4

Fill in the blanks.
In Glycolysis a cause of fatigue is hydrogen accumulation. This decreases __________. Leading to the inhibition of _________________ slowing down glycolysis which decreases ____ production. This slows down ______________ resulting in less power strokes interrupting muscle _________.

Answer 4

1. Blood PH
2. Phosphofructokinase (PFK)
3. ATP
4. Crossbridge cycles
5. Contraction

Question 5

True or false.
Does lactic acid cause Fatigue?

Answer 5

False.
The accumulation of hydrogen from lactic acid is what causes fatigue.

Question 6

Fill in the blanks.
Hydrogen accumulation causes fatigue in Glycolysis by decreasing ___________. This will inhibit the enzyme _______________ slowing down glycogenolysis. Therefore slowing _______ production causes less G6P to be made inhibiting the rate-limiting enzyme ______________ slowing down glycolysis. This lowers ________ production interrupting muscle _________.

Answer 6

1. Blood PH
2. Glycogen Phosphorylase
3. Glucose
4. Phosphofructokinase
5. ATP
6. Contraction

Question 7

Fill in the blanks.
Competitive inhibition is when _______ compete with calcium to bind with ________ that cover tropomyosin leading to less cross bridges and _________. Interrupting muscle _________ and resulting in muscle __________.

Answer 7

1. Hydrogen
2. Troponin
3. Power strokes
4. Contraction
5. Failure

Question 8

How does inorganic phosphate accumulation cause fatigue?

Answer 8

It inhibits the release of calcium from the sarcoplasmic reticulum.

Question 9

John is sprinting a 30-second sprint where he starts with his top speed until he can’t anymore resulting in a slower speed for the rest of race.

Describe the causes of fatigue John is feeling and determine what system would he finish with at the end of the race.

Answer 9

The cause of fatigue that John is feeling is the fatigue of the ATP-PCR system because of PCR depletion leading to the change of his pace. John would end the race in anaerobic glycolysis.

Question 10

Susan is attempting a 5 rep max bench press of 305lbs where at the last few reps she begins to struggle pushing the weight back up where at the last rep she had a spotter help her.

Describe a cause of fatigue that Susan is feeling and explain why?

Answer 10

The cause of fatigue that is Susan is feeling is the fatigue from her glycolysis system.

(All answers are provided)
The accumulation of hydrogen decreases her blood PH inhibiting phosphofructokinase slowing down glycolysis decreasing ATP production leading to muscle failure.

The accumulation of of hydrogen decreases her blood PH which inhibits glycogen phosphorylase slowing down glycogenolysis leading to less glucose production. Therefore less G6P inhibiting PFK slowing down glycolysis leading to less ATP production resulting in muscle failure.

Through competitive inhibition hydrogen competes with calcium to bind with troponin which covers tropomyosin. Interrupting muscle contraction and leads to muscle failure.

The accumulation of inorganic phosphate inhibits calcium release in the sarcoplasmic reticulum causing less cross bridges to form leading to less force produced eventually resulting in muscle failure.

Question 11

What are the three metabolic by-products that lead to fatigue?

Answer 11

Hydrogen, Lactic acid, and inorganic phosphate.

Question 12

What is neuromuscular fatigue?

Answer 12

A transient decrease in muscular performance seen as failure to maintain a certain force or power.

Question 13

What is acute muscle soreness and what causes it?

Answer 13

Pain felt during and immediately after exercising after strenuous physical activity.

It is caused by a buildup of metabolic-byproducts and tissue edema that cause the muscle to swell after exercising.

Question 14

What is Delayed On-set muscle soreness? (DOMS) What would you feel?

Answer 14

It is pain and soreness that is felt after a heavy exercise that is usually felt a day or two after.

They would feel an aching pain, muscle tenderness, muscle stiffness, and less force production from affected muscle.

Question 15

What are the two common sites of muscle damage that reduce force production during DOMS?

Answer 15

Z-Disk and contractile proteins (Actin/Myosin).

Question 16

What are the two theories behind exercise-induced muscle cramps?

Answer 16

Neuromuscular control theory - Occurs when some aspect of control between motor neuron and the muscle itself becomes altered. Excitation in muscle spindle and inhibition in golgi-tendon organ causing abnormal alpha-motor neuron behavior. Resulting in muscle twitches and eventually a cramp.

Electrolyte Depletion theory - Occurs when an athlete extensively sweats and has a significant electrolyte disturbance. Electrolyte depletion leads to motor nerve terminals to be hyperexcited creating more action potentials that eventually lead to a cramp.