Electrotherapy and Muscle Contraction Flashcards
When do we use accomodation
Chronic pain syndromes
True or False:
AP of muscle developed by electrically stimulated motor nerve is similar to that produced physiologically
True
How are motor units recruited during a contraction caused by E-stim
Large motor units are recruited first then small motor units
What does motor units being recruited from large motor to small units cause in terms of strength
The patient is weaker because the small motor units are not activated to help the large motor units
How are motor units recruited during a voluntary muscle contraction
Progressive recruitment of small, slow motor units to large fast motor units
What type of contraction has an increased rate of fatigue E-stim or voluntary
E-stim
True or False:
Longer rest times are needed between contractions to allow the muscle to be able to produce the same strength
True
What are the factors that influence the force-frequency relation for E-stim or voluntary contractions (4)
- Muscle length
- Muscle temperature
- Fatigue state
- Degree of potentiation of the muscle
What is low frequency stimulation of muscle with E-stim
1-2 stimuli per second
What does low frequency stimulation of muscle with E-stim cause
Twitch contraction
At what frequency will the AP start to summate causing unfused tetanus
15 pps
At what frequency will sustained contraction or tetanus occur
30 pps
What is the spatial motor unit recruitment for E-stim and voluntary muscle contraction
E-stim: Large to small
Voluntary: Small to large
What is the temporal motor unit recruitment for E-stim and voluntary muscle contraction
E-stim: Synchronous
Voluntary: Asynchronous
What is the muscle loading to increase strength for E-stim and voluntary muscle contraction
Both against resistance
What is the strengthening for E-stim and voluntary muscle contraction
E-stim: Increased motor unit recruitment and increased muscle hypertrophy
Voluntary: Increased motor unit recruitment and increased muscle hypertrophy
True or False:
E-stim can accelerate rehab by increasing muscle strength and endurance
True
What needs to happen to increase strength in healthy muscle
Stimulated contraction needs to be at least 50% of max voluntary isometric contraction (MVIC)
What needs to happen to increase strength in injured muscle
Stimulate contraction need to be only 10% of MVIC
Why do you not want a stronger contraction for injured muscle
It will produce greater pain and potential damage the tissue further
What is the overload theory
The larger the load placed on a muscle the greater the force of contraction the muscle will produce, thus strength will be greater than if smaller loads are applied
When does the overload theory apply to E-stim and voluntary muscle contractions
When the same force is applied
What is the specificity theory
E-stim stimulates large fast twitch type II motor units before small slow twitch motor units
True or False:
E-stim should produce greater strength gains than exercise alone with the same force contraction
True
Why is E-stim able to produce greater strength gains than exercise alone
Because it stimulates large motor units first which are the stronger motor units
What is the smoothness of onset of contraction for E-stim
Rapid and more jerky onset of contraction where all motor units of a given size contract simultaneously
True or False:
E-stim can support or assist with joint positioning
True it was able to reduce shoulder subluxations
True or False:
E-stim can increase blood flow
True
What frequency E-stim caused increased blood flow in the extremties
High frequency E-stim
How does blood flow increase because of E-stim
Muscle contraction increases venous return and muscles need more blood so heart pumps faster
True or False:
E-stim can treat urinary incontinence secondary to pelvic floor dysfunction
True
What is a denervated muscle
A muscle that does not receive input from a motor nerve