Effect of Electromyographic Biofeedback on Quadriceps Neuromuscular Function in Patients With Quadriceps Inhibition
| Status: | Terminated |
|---|---|
| Conditions: | Hospital, Orthopedic |
| Therapuetic Areas: | Orthopedics / Podiatry, Other |
| Healthy: | No |
| Age Range: | 18 - 40 |
| Updated: | 4/21/2016 |
| Start Date: | December 2013 |
| End Date: | August 2015 |
Effect of Electromyographic Biofeedback on Quadriceps Neuromuscular Function
Muscle inhibition prevents optimal contraction of the quadriceps muscle due to changes in
the nervous system after knee joint injury. Current treatments for muscle inhibition at this
time include knee joint cryotherapy and electric stimulation prior to exercise. These
treatments, in addition to strengthening exercises, have shown improvements in the quality
and strength of muscle contractions however, they have a short window of effectiveness.
Electromyographic Biofeedback is proven to be useful in improving quadriceps strength but
the mechanism of action remains somewhat unclear. Therefore, the purpose of this
investigation is to compare the effectiveness of electromyographic biofeedback supplemented
exercise when compared to traditional exercise on quadriceps muscle function in individuals
with a history of knee injury and current evidence of quadriceps inhibition. We hypothesize
that 14 days of electromyographic biofeedback supplemented exercise will lead to larger
gains in quadriceps activation when compared to traditional exercise.
Thirty 18-40 year old participants with a history of knee injury and current evidence of
quadriceps muscle inhibition will be enrolled in this single blind randomized controlled
trial. Participants will provide written consent prior to all study procedures. Following
enrollment, participants will be asked complete questionnaires related to knee related
function, current levels of pain, and current activity level followed by completion of
baseline measurements.
1. We will use the superimposed burst technique to quadriceps muscle activation.
2. We will measure the Hoffmann reflex response of the quadriceps with surface
electromyography. We will measure this signal with surface electromyography electrodes
that record the activity of the quadriceps muscle through the skin.
Participants in both groups will be instructed on a 14 day home exercise protocol on the day
of enrollment. The protocol is comprised of 4 exercises focused on both non-weight bearing
and weight bearing quadriceps strengthening. Compliance will be monitored via a daily
exercise diary which will be collected at the end of the study protocol.
Quadriceps central activation ratio, active motor threshold and Hoffmann reflex will be
reported descriptively. Pre-intervention and post 14 day intervention quadriceps central
activation ratio and Hoffmann reflex will be compared between traditional exercise and
Biofeedback supplemented exercise
the nervous system after knee joint injury. Current treatments for muscle inhibition at this
time include knee joint cryotherapy and electric stimulation prior to exercise. These
treatments, in addition to strengthening exercises, have shown improvements in the quality
and strength of muscle contractions however, they have a short window of effectiveness.
Electromyographic Biofeedback is proven to be useful in improving quadriceps strength but
the mechanism of action remains somewhat unclear. Therefore, the purpose of this
investigation is to compare the effectiveness of electromyographic biofeedback supplemented
exercise when compared to traditional exercise on quadriceps muscle function in individuals
with a history of knee injury and current evidence of quadriceps inhibition. We hypothesize
that 14 days of electromyographic biofeedback supplemented exercise will lead to larger
gains in quadriceps activation when compared to traditional exercise.
Thirty 18-40 year old participants with a history of knee injury and current evidence of
quadriceps muscle inhibition will be enrolled in this single blind randomized controlled
trial. Participants will provide written consent prior to all study procedures. Following
enrollment, participants will be asked complete questionnaires related to knee related
function, current levels of pain, and current activity level followed by completion of
baseline measurements.
1. We will use the superimposed burst technique to quadriceps muscle activation.
2. We will measure the Hoffmann reflex response of the quadriceps with surface
electromyography. We will measure this signal with surface electromyography electrodes
that record the activity of the quadriceps muscle through the skin.
Participants in both groups will be instructed on a 14 day home exercise protocol on the day
of enrollment. The protocol is comprised of 4 exercises focused on both non-weight bearing
and weight bearing quadriceps strengthening. Compliance will be monitored via a daily
exercise diary which will be collected at the end of the study protocol.
Quadriceps central activation ratio, active motor threshold and Hoffmann reflex will be
reported descriptively. Pre-intervention and post 14 day intervention quadriceps central
activation ratio and Hoffmann reflex will be compared between traditional exercise and
Biofeedback supplemented exercise
Screening Subjects will be asked to complete a brief questionnaire about their lower
extremity, which will be used to determine if they exhibit any of the exclusionary criteria
(administered by the Study Coordinator). This will include past medical history, headache/
migraine history, and any drugs/medications they are currently taking (which might influence
the excitability threshold Hoffman reflex (H-reflex) measurement or central activation
ratio). Subjects will also undergo quadriceps central activation ratio testing to determine
the level of quadriceps inhibition. Upon review of the questionnaire and quadriceps central
activation ratio, the study coordinator will determine a subject's eligibility (based on the
inclusion and exclusion criteria). We will also collect age, height and weight for all
subjects. Participants that qualify will provide written at this time which will be
documented by the investigator.
Quadriceps Central Activation Ratio We will use the superimposed burst technique to measure
quadriceps muscle strength and to estimate quadriceps activation by calculating the central
activation ratio. Subjects will be secured to a chair (Biodex multi-mode dynamometer) with
their knees and hips bent to approximately 90 degrees. Subjects will perform a maximal,
voluntary isometric knee extension contraction (MVIC) with continuous verbal encouragement
from the tester. Once the MVIC reaches a plateau (representing subjects' maximal effort) an
electrical stimulus will be manually triggered and delivered directly to the quadriceps
through 2 stimulating electrodes which will be secured to the subjects' anterior thigh. The
stimulus will cause the quadriceps to twitch resulting in a temporary increase in force
production which we will measure. A ratio between the MVIC force and the highest force
achieved due to the electrical stimulation will be calculated - this is called the central
activation ratio. The electrical stimulus will be delivered manually with a square-wave
stimulator in conjunction with a stimulus isolation unit) and will consist of a train of 10
consecutive, square wave pulses of 600 microsecond duration, at an intensity of 125 volts
with a carrier frequency of 100 pulses per second. Subjects will have the option of
experiencing some "practice" pulses at lower intensity in order to become acclimated to the
stimulus and the practice maintaining maximum effort in anticipation of the stimulation.
Randomization Randomization will take place after enrollment and screening take place. The
assessor will be blinded in this investigation. Therefore, the clinician responsible for
educating patients regarding the exercise protocols will also be responsible for
randomization. Randomization will take place on a 1:1 basis. Prior to starting the study, a
binary random number generator will be used to generate the randomization scheme. These
numbers will then by placed in sealed envelopes and label with individual subject numbers.
The randomization envelopes will be stored in a locked drawer and will only be removed by
the clinician responsible for randomization. The randomization envelope will then be stored
in the participant's research folder.
Quadriceps Hoffmann Reflex We will record muscle reflex activity by delivering a short
percutaneous (through the skin) electrical stimulation to femoral nerve located in the
inguinal fold. We will measure the reflex response of the quadriceps with surface
electromyography. This measure helps to describe the function of a muscle before and after
our exercise protocol. Subjects will be positioned comfortably in a lying-down position on a
treatment table. Stimuli will be delivered to the femoral nerve by increasing the intensity
in small increments with a 10 second rest interval after each stimulus, until the maximum
H-reflex amplitude is recorded (Hmax). Then we will increase the stimulus voltage until we
obtain a maximum M-wave. The H-reflex represents the proportion of the quadriceps motor
neuron pool that is available for voluntary contraction and the M-wave represents the total
volume of the quadriceps motor neuron pool and will be used to normalize the H-reflex
recordings as H:M ratio. This measurement will be performed bilaterally.
Exercise Intervention Participants in both groups will be instructed on a 14 day exercise (4
supervised session and 10 home sessions) protocol on the day of enrollment. The protocol is
comprised of 4 exercises focused on both non-weight bearing and weight bearing quadriceps
strengthening. All participants will be asked to complete 3 set of 10 repetitions of
isometric quadriceps contractions with a 15 second hold time, supine straight leg raises,
body weight squatting, and body weight lunges daily. Participants will be required to
complete the single limb exercises on the previously injured limb only. A compliance log
will be given to each participant and will be reviewed at each supervised exercise session
and at the final study visit. Participants will be instructed to discontinue exercise and
contact the principle investigator if they experience knee pain due to the intervention.
Participants in the electromyographic biofeedback supplemented exercise will also be
instructed on correct setup and use of the electromyographic biofeedback unit. These
instructions will focus on correct placement of the electromyography recording electrodes
over quadriceps muscle as well as correct tuning of the feedback threshold for each exercise
to maximize the benefit of the intervention. Electromyographic biofeedback will be used
during all exercises throughout the course of the study for this group.
Follow-up Testing After 14±1 days of exercise intervention all baseline measures will be
re-tested in the same manner as explained above. A supervised exercise session and
compliance check will be completed 3±1, 7±1, and 10±1 days following enrollment into the
study. No follow-up measurements will be taken at this point, however an exercise compliance
log will be collected from all participants.
extremity, which will be used to determine if they exhibit any of the exclusionary criteria
(administered by the Study Coordinator). This will include past medical history, headache/
migraine history, and any drugs/medications they are currently taking (which might influence
the excitability threshold Hoffman reflex (H-reflex) measurement or central activation
ratio). Subjects will also undergo quadriceps central activation ratio testing to determine
the level of quadriceps inhibition. Upon review of the questionnaire and quadriceps central
activation ratio, the study coordinator will determine a subject's eligibility (based on the
inclusion and exclusion criteria). We will also collect age, height and weight for all
subjects. Participants that qualify will provide written at this time which will be
documented by the investigator.
Quadriceps Central Activation Ratio We will use the superimposed burst technique to measure
quadriceps muscle strength and to estimate quadriceps activation by calculating the central
activation ratio. Subjects will be secured to a chair (Biodex multi-mode dynamometer) with
their knees and hips bent to approximately 90 degrees. Subjects will perform a maximal,
voluntary isometric knee extension contraction (MVIC) with continuous verbal encouragement
from the tester. Once the MVIC reaches a plateau (representing subjects' maximal effort) an
electrical stimulus will be manually triggered and delivered directly to the quadriceps
through 2 stimulating electrodes which will be secured to the subjects' anterior thigh. The
stimulus will cause the quadriceps to twitch resulting in a temporary increase in force
production which we will measure. A ratio between the MVIC force and the highest force
achieved due to the electrical stimulation will be calculated - this is called the central
activation ratio. The electrical stimulus will be delivered manually with a square-wave
stimulator in conjunction with a stimulus isolation unit) and will consist of a train of 10
consecutive, square wave pulses of 600 microsecond duration, at an intensity of 125 volts
with a carrier frequency of 100 pulses per second. Subjects will have the option of
experiencing some "practice" pulses at lower intensity in order to become acclimated to the
stimulus and the practice maintaining maximum effort in anticipation of the stimulation.
Randomization Randomization will take place after enrollment and screening take place. The
assessor will be blinded in this investigation. Therefore, the clinician responsible for
educating patients regarding the exercise protocols will also be responsible for
randomization. Randomization will take place on a 1:1 basis. Prior to starting the study, a
binary random number generator will be used to generate the randomization scheme. These
numbers will then by placed in sealed envelopes and label with individual subject numbers.
The randomization envelopes will be stored in a locked drawer and will only be removed by
the clinician responsible for randomization. The randomization envelope will then be stored
in the participant's research folder.
Quadriceps Hoffmann Reflex We will record muscle reflex activity by delivering a short
percutaneous (through the skin) electrical stimulation to femoral nerve located in the
inguinal fold. We will measure the reflex response of the quadriceps with surface
electromyography. This measure helps to describe the function of a muscle before and after
our exercise protocol. Subjects will be positioned comfortably in a lying-down position on a
treatment table. Stimuli will be delivered to the femoral nerve by increasing the intensity
in small increments with a 10 second rest interval after each stimulus, until the maximum
H-reflex amplitude is recorded (Hmax). Then we will increase the stimulus voltage until we
obtain a maximum M-wave. The H-reflex represents the proportion of the quadriceps motor
neuron pool that is available for voluntary contraction and the M-wave represents the total
volume of the quadriceps motor neuron pool and will be used to normalize the H-reflex
recordings as H:M ratio. This measurement will be performed bilaterally.
Exercise Intervention Participants in both groups will be instructed on a 14 day exercise (4
supervised session and 10 home sessions) protocol on the day of enrollment. The protocol is
comprised of 4 exercises focused on both non-weight bearing and weight bearing quadriceps
strengthening. All participants will be asked to complete 3 set of 10 repetitions of
isometric quadriceps contractions with a 15 second hold time, supine straight leg raises,
body weight squatting, and body weight lunges daily. Participants will be required to
complete the single limb exercises on the previously injured limb only. A compliance log
will be given to each participant and will be reviewed at each supervised exercise session
and at the final study visit. Participants will be instructed to discontinue exercise and
contact the principle investigator if they experience knee pain due to the intervention.
Participants in the electromyographic biofeedback supplemented exercise will also be
instructed on correct setup and use of the electromyographic biofeedback unit. These
instructions will focus on correct placement of the electromyography recording electrodes
over quadriceps muscle as well as correct tuning of the feedback threshold for each exercise
to maximize the benefit of the intervention. Electromyographic biofeedback will be used
during all exercises throughout the course of the study for this group.
Follow-up Testing After 14±1 days of exercise intervention all baseline measures will be
re-tested in the same manner as explained above. A supervised exercise session and
compliance check will be completed 3±1, 7±1, and 10±1 days following enrollment into the
study. No follow-up measurements will be taken at this point, however an exercise compliance
log will be collected from all participants.
Inclusion Criteria:
- History of primary and uncomplicated knee injury or knee surgery.
- Aged 18-40
- Quadriceps Central Activation Ratio is less than 90%
Exclusion Criteria:
- Currently seeking physical therapy
- Complex knee injury
- Surgical revisions to original procedure
- Pain greater than 4 out of 10 on a visual analog scale at enrollment.
- Active infection
- Current pregnancy
- Cognitive impairment
- Psychiatric disorder requiring daily medication
- Chronic or acute neuropathy
- Known muscular abnormalities
- History of neurological disorders
- History or family history of seizures and/or epilepsy and/or on medications that
lower seizure threshold
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