Quiz 2 Flashcards
Current density:
If one electrode of a stimulating pair is physically smaller than the other, it will have a higher density of current under it
Voluntary contraction uses what kind of fibers first?
Type I : slow twitch (oxidative, low force, resist fatigue)
Stimulated contraction uses what kind of fibers first?
Type II (glycolytic, high force, fatigue quickly)
Electrical stimulation contraction what muscle fibers first and why?
fast twitch Type II: large diameter motor neuron
Voluntary muscle contraction is :
smooth onset
asynchronous recruitment of motor units
Stimulated contraction:
rapid (can be jerky) onset
synchronous recruitment of motor units
Pulse duration for small muscles:
150-200 us
Pulse duration for large muscles
200-350 us
Pulse frequency for twitch:
less than 20 pps
Pulse frequency for tetany:
35-50 pps
Pulse frequency for fatigue:
greater than 50 pps
Pulse frequency for strengthening:
up yo 80 pps
On: off time for building strength
6-10 sec ON time
on: off ration 1:5, 1:4 or 1:3
On: off time for fatiguing spasm
2-5 sec ON time
ON; OFF ratio 1:1
On: off time for edema reduction:
2-5 sec On time
on: off ratio 1:1
Ramp time for strength building contractions:
2-4 sec (longer ramp)
Ramp time for weaker contractions:
1-2 sec
What situations may require no ramp?
active dorsiflexion assist during gait
What situations may require extended ramp?
antagonist to spastic muscle
Treatment time for muscle strengthening:
10-20 contractions
Treatment time for muscle reeducation:
depends on activity
Treatment time for muscle spasm reduction:
10-30 mins
Treatment time for edema reduction (muscle pump)
30 mins
