Flashcards in PT Deck (33):
What is the stimulation principle for NMES?
current induced must be sufficient amplitude and duration to maintain muscle excitement
With electrically recruited motor fibers, which is recruited first, type I or Type II?
Type II Fast twitch fibers d\t larger diametier of neurons
With voluntary contraction, whcih motor units are recruited first type or Type II?
Type I slow twitch b\c they take longer to fatigue
3 things that the muscle force generation is determined by.
Type of muscle fibers, number of motor units, and rate coding\temporal summation.
TF: Training uscles w repetitiive contractions of external load will induce muscle fiber hypertrophy.
4 physiological effects of NMES
1. recruites fast twitch fibers 2. synchronous contraction of fibers
3. deactivatess GTO 4. increase in metabolic efficiency after immobilization
As a result of NMES, the muscles have a increased injury potential? Why?
A physiologic effect of NMES is to inactivate the GTO, which normally protects the muscle.
Indications for NMES include? 6
muscle strengthning, increase ROM, and treatment of disuse dtt atrophy, mscl re education, spasticity management, functional electrical stimulation
Describe the waveform for russian current
biphasic, symmetrical, balance, continuous sine wave in bursts of 10 sec on and 50 sec off
What is the relationship b\t pulses and physiological effects?
No relationship, number of pulses in a burst is independent of phys effect
What is the relationship b\tt bursts and physio effects
Number of bursts per second determines the magnitude of physio effects
What is the importance of a medium frequency range of sine waves?
medium frequency shortens the pulse duration and charge, leading to the skin decreasing resitance and allows deeper pentration
What is the importance of mediu frequency sine waves on nerve stimulation?
nerve depolarizes and doesn
t have sufficient time to re polarize, so the nerve is in a constant stae of depolarization, blocking nerve signals. Called Wedinsky Inhibition
Painlss muscle contraction is supposedly cause by this concept
Overall effects of russian current
stronger than voluntary contractions, deeper tissue stimulation, painless, recruits fast twitch motor uits and increases mscl strength
Indications for russian current 4
Strengthen mscl of healthy individuals, muscle spasm, muscle atrophy, circulatory disorders
Major contraindicatio to russian current is
situations where contraction is not wanted. fractures, cysts, dislocations, osteoporosis
Burst frequency for Russian current, 10 bps, 50 bps, 150 bps 500 bps
When during the day will an athlete see the bestt results from russian current?
at night time before bed, 10-25 reps, 20-25 sessions
In order for ultrasound to travel, it requires a ?
medium liquid, the denser the better
solid materials can be electrically charged when they are mechanically stresssed.
Reverse piezoelectrical effect
When a high frequency, alternting electrical current is applied on surface of pioelectric materials, a mechanical deformatio occurs in form of oscillations of the material.
repeated cycles of micro expansion and micro contraction of the piezoelectric material push the surrounding air in alternate waves of compression and rarefaction that produce ultrasonic beam of energy
low pressure waves that allow molecules to move further apart
high pressure waves that push each molecule together
location where high frequency, alternating current is aplied to th piezoelectric material
Ultrasound passes through 3?
sound, air, human tissues
Difference between longitudinal and transverse waves
Longitudinal: direction of motion of molecules is parallell to direction of wave propagation
Transverse: direction of motion of molecules is perpendicular to the direction of wave propagation
Body tissues transmit only BLANKKK waves where as Bone and solids transmit only BLANKKK
Body tissues: Longitudinal
Solids: transverse and longitudinal
TF the US beam intensity is homogenous and unifom throughout the beam axis
BLANKK the frequency the BLANKKK the beam diverges
Higher the frequency, the less the beam diverges
What is the Beam Non uniformity Ratio
The ratio of intensity of highest peak to that of the average intensity at all peaks, the lower the BNR the lower the probability of a hot spot during treatment