Effect of Electromyographic Biofeedback on Quadriceps Neuromuscular Function in Patients With Quadriceps Inhibition

Summary

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

Conditions

• Knee Injuries

Interventions

DEVICE

Electromyographic Biofeedback

Electromyographic biofeedback is a device that enables a patient or clinician to measure the intensity of a muscle contraction using electrodes placed on the skin over a muscle of interest. In this study, 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 electromyographic 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.

BEHAVIORAL

Traditional Exercise

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.

Sponsors & Collaborators

• University of Miami

  lead OTHER

Principal Investigators

• Christopher Kuenze, PhD · University of Miami

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

SINGLE

Model

PARALLEL

Eligibility

Min Age

18 Years

Max Age

40 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2013-12-31

Primary Completion

2015-08-31

Completion

2015-08-31

Countries

• United States

Study Locations