Lecture 11: Fatigue and Training Flashcards
What is Fatigue? (general definitions)
Decline in:
- performance
- muscle activation by CNS
- force of muscle contraction (most common measure)
What are additional effects of Fatigue?
Changes in:
- Reflex effects
- general motor command
- motivation
What are (2) types of Fatigue?
Central Fatigue & Peripheral Fatigue
What is Central Fatigue?
Alpha Motor Neuron up to the CNS
What is Peripheral Fatigue
Neuromuscular junction outward
True or False: CNS adaptations due to Fatigue CAN IMPROVE or WORSEN performance
True
Why is conduction velocity of action potential along the muscle fiber slow down?
Decrease in Sodium & Potassium to cross membrane
What are (2) reasons for reduced contraction strength in response to an AP?
- caused by shortage of chemical fuel
* inability to quickly remove products of muscle metabolism that can interfere with contraction
Why would relaxation of muscle contraction slow down?
- Less ATP
* Slower Ca Removal
What are effects of the relaxation phase of muscle contraction slowed?
Help movement smooth out, more smooth movement
How can an EMG measure fatigue?
- listen to a motor unit (frequency)
* Analyze frequency power spectrum of entire EMG signal
What is Henneman principle?
Larger, faster motor unit decreases more dramatically
Other: Smaller, slow twitch maintains firing frequency longer
So, which motor neurons should you use first if your running a marathon?
small neurons
As you start fatiguing, you should increase motor unit frequency but maintain force. Therefore to stay in homeostasis, you should _______ motor units
decrease
If you increase force to maintain, but then decide to burst, you would need to ….? But this can ______ symptoms when finally fatigues.
Synchronize of motor unit discharge ; Tremor Systems
What would inducing hypertrophy lead and neuromuscular adaptations to?
increasing strength
What would changing cytoskeleton of muscle fibers lead to?
increase strength
What are (2) pieces of evidence that proves strength gain is purely neurological, not physical?
- ) Dissociative Strength Gains
2. ) Specifity of Strength Gains
What is Dissociative Strength Gains?
Seeing increase in strength but no change in muscle size
What is Specificity of Strength Gains?
Increase of strength due to one training force as opposed to other tasks
Where do neurological strength gains occur?
Coordination & Activation Maximally
Where do strength gains occur?
plasticity in CNS
Define Neuromuscular Training. What is the goal of this training?
Supplementing a Maximal Voluntary Contraction ( MVC) with electrical stimulation
GOAL: Increased activation and force production
What are (2) problems of Neuromuscular Training?
- stimulation discomfort in increase of activation that can be achieved
- Fatigue occurs more rapidly
