Lecture 11: Fatigue and Training

Question 1

What is Fatigue? (general definitions)

Answer 1

Decline in:

• performance
• muscle activation by CNS
• force of muscle contraction (most common measure)

Question 2

What are additional effects of Fatigue?

Answer 2

Changes in:

• Reflex effects
• general motor command
• motivation

Question 3

What are (2) types of Fatigue?

Answer 3

Central Fatigue & Peripheral Fatigue

Question 4

What is Central Fatigue?

Answer 4

Alpha Motor Neuron up to the CNS

Question 5

What is Peripheral Fatigue

Answer 5

Neuromuscular junction outward

Question 6

True or False: CNS adaptations due to Fatigue CAN IMPROVE or WORSEN performance

Answer 6

True

Question 7

Why is conduction velocity of action potential along the muscle fiber slow down?

Answer 7

Decrease in Sodium & Potassium to cross membrane

Question 8

What are (2) reasons for reduced contraction strength in response to an AP?

Answer 8

• caused by shortage of chemical fuel

* inability to quickly remove products of muscle metabolism that can interfere with contraction

Question 9

Why would relaxation of muscle contraction slow down?

Answer 9

• Less ATP

* Slower Ca Removal

Question 10

What are effects of the relaxation phase of muscle contraction slowed?

Answer 10

Help movement smooth out, more smooth movement

Question 11

How can an EMG measure fatigue?

Answer 11

• listen to a motor unit (frequency)

* Analyze frequency power spectrum of entire EMG signal

Question 12

What is Henneman principle?

Answer 12

Larger, faster motor unit decreases more dramatically

Other: Smaller, slow twitch maintains firing frequency longer

Question 13

So, which motor neurons should you use first if your running a marathon?

Answer 13

small neurons

Question 14

As you start fatiguing, you should increase motor unit frequency but maintain force. Therefore to stay in homeostasis, you should _______ motor units

Answer 14

decrease

Question 15

If you increase force to maintain, but then decide to burst, you would need to ….? But this can ______ symptoms when finally fatigues.

Answer 15

Synchronize of motor unit discharge ; Tremor Systems

Question 16

What would inducing hypertrophy lead and neuromuscular adaptations to?

Answer 16

increasing strength

Question 17

What would changing cytoskeleton of muscle fibers lead to?

Answer 17

increase strength

Question 18

What are (2) pieces of evidence that proves strength gain is purely neurological, not physical?

Answer 18

1. ) Dissociative Strength Gains

2. ) Specifity of Strength Gains

Question 19

What is Dissociative Strength Gains?

Answer 19

Seeing increase in strength but no change in muscle size

Question 20

What is Specificity of Strength Gains?

Answer 20

Increase of strength due to one training force as opposed to other tasks

Question 21

Where do neurological strength gains occur?

Answer 21

Coordination & Activation Maximally

Question 22

Where do strength gains occur?

Answer 22

plasticity in CNS

Question 23

Define Neuromuscular Training. What is the goal of this training?

Answer 23

Supplementing a Maximal Voluntary Contraction ( MVC) with electrical stimulation

GOAL: Increased activation and force production

Question 24

What are (2) problems of Neuromuscular Training?

Answer 24

• stimulation discomfort in increase of activation that can be achieved
• Fatigue occurs more rapidly

Question 25

Why would electrodes fatigue muscles faster than naturally trying to build muscle?

Answer 25

• Locking only one muscle to work their fast twitch fibers, making it to fatigue faster with no time to recover
• fast twitch fibers are on the surface, there fore tire quicker
• Synchronization nature of artificial activation (more work on muscle)

Question 26

Normal exercise is better than neuromuscular training, but great for Senior citizens. Why?

Answer 26

Use of less muscles and bed ridden, most you could do is electrode stimulation

Question 27

Why would Vibration Training be not as great as real exercise?

Answer 27

less impact