Term
| what is the recruitment order of nerve fibers for volitional contractions |
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Definition
| smal diameter nerve fibers before large diameter nerve fibers |
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Term
| what is the recruitment order of motor units for volitional contractions |
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Definition
| slow twitch motor units before fast twitch motor units |
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Term
| why are slow twitch motor units activated before fast twitch motor units in volitional contractions/ |
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Definition
| slow twitch motor units are innervated by smaller diameter nerves; fast twitch motor units are innervated by larger diameter nerves |
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Term
| what is the purpose of activating slow twitch motor units before fast twitch motor units in volitional contractions |
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Definition
| Allows you to move smoothly. You start with slow twitch to guage what you need first. The heavier something is or the faster you have to move, the more fast twitch you have to bring in. |
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Term
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Definition
| the frequency of action potentials required to get the reaction you need |
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Term
| describe rate coding of volitional contractions |
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Definition
| motor units activate asynchronously. They go from motor unit to motor unit to avoid fatigue and to keep the muscle contraction going at the level you need it. |
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Term
| what is the path of the signal in volitional muscle contraction |
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Definition
| signal goes from brain - spinal cord - skeletal motor nerves - muscle contracts |
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Term
| what is the recruitment order of nerve fibers for electrical contractions |
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Definition
|
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Term
| what determines the recruitment order of nerve fibers for electrical contractions |
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Definition
| distance of nerves from the electrodes |
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Term
| if 2 nerves are the same distance from stimulation, what determines the recruitment order of nerve fibers for electrical contractions |
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Definition
| the largest diameter nerves will be activated first |
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|
Term
| why are large diameter nerve fibers activated first in electrical stimulation |
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Definition
| large diameter = lower internal resistance |
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Term
| describe rate coding of electrical contractions |
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Definition
| synchronous: all motor units fire or they don't fire at all. They all fatigue and drop out simultaneously |
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|
Term
| what is the recruitment order of motor units for electrical contractions |
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Definition
| fast twitch motor units before slow twitch motor units |
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Term
| describe rate coding of volitional contractions as you start to fatigue |
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Definition
| become more syncrhonous as fatigue occurs and motor units start to drop out. Causes vibration |
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Term
| does electrical stimulation only activate motor fibers? |
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Definition
| also activate peripheral sensory fibers as well as nerve fibers of the autonomic nervous system |
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Term
| positive things you get from muscle stimulation |
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Definition
| same metabolic reactions you get from contracting muscles on your own. Improve endurance, function, some strength |
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Term
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Definition
| only good for strengthening one or a few muscles at a time |
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Term
| what are the desired adaptations caused by stimulating a muscle for strength |
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Definition
| hypertrophy of muscle fibers; increase in number of contractile proteins |
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Term
| describe the type of contractions you want to adapt to in muscle strengthening |
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Definition
| intermittent, high force contractions |
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Term
| how much should you stimulate for strengthening and why |
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Definition
| because fast twitch fibers are activated first, you only need to stimulate at 50% 10RM to overload the muscle (which tells the muscle that it needs more protein.) |
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Term
| what are the desired adaptations caused by stimulating a muscle for endurance |
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Definition
| not after fatigue; want to make adaptations to prolonged, low force contractions |
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Term
| what changes occur in the muscle as it adapts to prolonged, low force contractions for endurance |
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Definition
| increased activity of oxidative enzymes, increased number of mitochondria, increased myoglobin content, increased number of capillaries to muscle fibers |
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Term
| if you're doing muscle stimulation for functional activities like walking, will you stimulate for strength or endurance |
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Definition
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Term
| what is the threshold level for strengthening with e-stim |
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Definition
|
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Term
| what is the threshold level for strengthening with voluntary contractions |
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Definition
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Term
| is there a given current that will stimulate the maximum number of motor axons and the minimum number of nociceptors |
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Definition
|
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Term
| how do you set the current amplitude |
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Definition
| set the amplitude based on your “goal” or purpose for the muscle contraction |
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Term
| what to set the current amplitude to for a weak, compromised muscle group |
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Definition
| set to 10% of what the uninvolved side can do to get to the threshold that the muscle needs to improve |
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Term
| what is the most common waveform for muscle stimulation |
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Definition
|
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Term
| how to determine current amplitude when there isn't an uninvolved side |
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Definition
| start at a low level and work up to the contraction you want |
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Term
| how to set current amplitude for someone with an SCI |
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Definition
| can be higher because they can't feel it. You can get strong enough contractions to stand them up. |
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Term
| if you have a setup and you aren't getting the reaction you want, what can you change? |
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Definition
| spread electrodes farther apart so that current will go deeper, increase intensity, increase duration |
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Term
| goal for frequency in muscle strengthening |
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Definition
| high enough to produce a smooth or tetanic contraction |
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Term
| what frequency is sufficient to achieve a tetanic contraction in most healthy human skeletal muscle |
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Definition
|
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Term
| is frequency related to pulse duration in a pulsed waveform? |
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Definition
|
|
Term
| how many muscle twitches do we get when the frequency is 5 pps |
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Definition
|
|
Term
| what is the muscle response to a frequency of 15pps |
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Definition
| subtetanic because the muscle fibers don’t have a change to fully relax before the next action potential contracts them again |
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|
Term
| what frequency is tetanic |
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Definition
|
|
Term
| at what point of frequency does the muscle begin to fatigue |
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Definition
|
|
Term
| what is the range of adequate frequency for muscle force for most people |
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Definition
|
|
Term
| is it good to go above 75pps for muscle strengthening? |
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Definition
| no. the muscle fatigues too quickly |
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|
Term
| why must the stimulation be cycled on and off? |
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Definition
| more functional; avoids fatigue |
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|
Term
| what is the on:off ratio for muscle stimulation for strengthening |
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Definition
| 10-15 seconds of contraction: 50-120 seconds of rest |
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Term
| what is the best on:off ratio for people who are very strong |
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Definition
|
|
Term
| what is the best on:off ratio for people who are very weak |
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Definition
|
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Term
| if a person is very weak and you start with 10:50 on:off time, how do you progress? |
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Definition
|
|
Term
| what is the lowest on:off ratio to use for someone who is weak but progressing |
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Definition
|
|
Term
| should the on or off time be greater? |
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Definition
| off time should be greater |
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|
Term
| why should off time be greater than on time? |
|
Definition
| less fatigue, more building of muscle mass |
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|
Term
| is a greater intensity needed for strength or for function? |
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Definition
|
|
Term
| what is the typical pulse duration range for NMES |
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Definition
|
|
Term
| what is the purpose of ramping on/off |
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Definition
|
|
Term
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Definition
| time it takes the device to get from the minimum intensity to the maximum intensity that you're going to use |
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Term
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Definition
| time it takes to get from 0 to the peak for one individual phase |
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|
Term
| what is the result of using an electrode that is too big |
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Definition
| disperses current over too large an area, decreasing current density and therefore contraction |
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|
Term
| what determines size of electrode to use |
|
Definition
| size of muscle being activated |
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|
Term
| how does contraction intensity related to strength gains |
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Definition
| increasing contraction intensity increases strength gain |
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|
Term
|
Definition
| time of contraction vs. rest |
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|
Term
| is there an optimal pulse duration for muscle strengthening? |
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Definition
| no, just the range of 200-600 microseconds. Determine what is best for the individual |
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|
Term
| how does intensity change the depth of stimulation and number of motor units activated |
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Definition
| greater intensity increases depth of stimulation and number of motor units activated |
|
|
Term
| how does electrode placement change the depth of stimulation and number of motor units activated |
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Definition
| electrodes spread farther apart increases depth of stimulatiion and number of motor units activated |
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|
Term
| what type of frequency is used with russian current |
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Definition
|
|
Term
| what is the parameter for medium frequency |
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Definition
|
|
Term
| how large are the contractions produced by russian current with medium frequency? |
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Definition
|
|
Term
|
Definition
| muscle voluntary isometric contraction |
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|
Term
| can you get strength improvements with low frequency currents |
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Definition
|
|
Term
| how to exercise both slow and fast twitch fibers |
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Definition
| patient exercises with muscle stimulation. Muscle stimulation turns on fast twitch, volitional turns on slow twitch |
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Term
| The following questions refer to how to gain strength in lumbar region that has inhibition from swelling |
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Definition
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Term
|
Definition
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Term
|
Definition
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Term
|
Definition
|
|
Term
|
Definition
|
|
Term
| where to center the electrodes |
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Definition
|
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Term
|
Definition
|
|
Term
|
Definition
| muscle spasm to try and fatigue the muscle |
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|
Term
|
Definition
| contraction-relaxation pattern |
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|
Term
| how to activate both slow and fast motor units |
|
Definition
| patient does lumbar extension exercises during muscle stimulation |
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|
Term
| on:off ratio to strengthen a weak muscle |
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Definition
|
|
Term
| on:off ratio for functional |
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Definition
|
|
Term
| on:off ratio for muscle pump |
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Definition
|
|
Term
| if phase duration is 20us, what is pulse duration? |
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Definition
|
|
Term
| difference between phase and pulse |
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Definition
| phase is either pos or negative, pulse is both compined |
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|
Term
| if pulse duration is 60, what is phase duration |
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Definition
|
|
Term
| how do we describe the direction of current flow? |
|
Definition
| the direction of the movement of positive particles/ions (opposite direction of electrons) |
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|
Term
| what generates action potentials |
|
Definition
| discharging the membrane capacitor, which opens the voltage gated channels |
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|
Term
| where is the potassium battery? |
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Definition
|
|
Term
| where is the sodium battery? |
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Definition
|
|
Term
| if we place a positive and a negative electrode near a nerve, what will the positive ions from the capacitor do? |
|
Definition
| go towards negative electrode. This change in the position of ions changes the membrane potential. The inside wall will become +, the outside -. The change in voltage triggers the voltage senstive sodium ion channels to open, starting the action potential |
|
|
Term
| what will happen to negative ions in the cell if we place electrodes near a nerve? |
|
Definition
| negative ions will be pulled upward by the positive electrodes, which have moved towrads the negative electrode |
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|
Term
| with the placement of electrodes near a nerve, how has the capacitor changed? |
|
Definition
| capacitor has been discharged. |
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|
Term
| how does the discharging of the capacitor affect the cell? |
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Definition
| the change in polarity of the cell causes the sodium channel to open so that sodium can flow in. a few miliseconds later, the potassium channel opens and potassium flows out. |
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|
Term
| what is the membrane potential for a steady state |
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Definition
|
|
Term
| what is the firing threshold when sodium channels open |
|
Definition
|
|
Term
| what happens after sodium channels open and sodium peaks inside? |
|
Definition
|
|
Term
| what happens after potassium channels open? |
|
Definition
| potassium flows out and sodium is pumped out |
|
|
Term
| what happens as potassium and sodium both leave |
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Definition
|
|
Term
| what happens to reduce hyperpolarization |
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Definition
| pumps return ions to steady state |
|
|
Term
| how long is the absolute refractory period? |
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Definition
|
|
Term
| what is the absolute refractory period |
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Definition
| the time of the action potential when the action potential can't be stopped and can't be repeated |
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|
Term
| when is the relative refractory period |
|
Definition
| the last 1/3 of repolarization to baseline return |
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