Combined Application of Electrical Stimulation and Volitional Contractions for Muscle Strengthening and Knee Pain Inhibition (Seated Study)

Not Applicable

Completed

Conditions: Knee Osteoarthritis

Interventions: Device: Hybrid Training using Electrodes and Joint Motion Sensors
Device: Isokinetic Training with Isokinetic Dynamometer

Registration Number: NCT02802878

Lead Sponsor: University of Kansas Medical Center

Brief Summary: The purpose of this study is to assess the efficacy of a 12-week low-load neuromuscular electrical stimulation with volitional contraction (NMES-VC) training program to improve quadriceps strength and activation, while not adversely affecting knee-related pain, activities of daily living or quality of life in women with knee pain. The primary outcome will be change in maximal isokinetic knee extensor torque.

The investigators will test the following hypotheses. In comparison with low-load (40%) resistance training without electrical stimulation, a 12-week NMES-VC training program will:

Hypothesis 1: Increase maximal isokinetic knee extensor torque

Secondary questions and response variables

Hypothesis 2: Not adversely affect knee pain or quality of life, assessed by the Knee injury and Osteoarthritis Outcome Score (KOOS) questionnaire

Additional hypotheses in women with risk factors for incident symptomatic or progressive KOA:

1. Determine the extent to which NMES-VC-enhanced low-intensity resistance training increases quadriceps muscle rate of force development

2. Determine the extent to which NMES-VC enhanced low-intensity exercise is tolerated (using numeric rating scale survey "level of pain you experienced during the hybrid training or 40% isokinetic exercise")

3. Determine the extent to which NMES-VC-enhanced low-intensity resistance training increases physical function (20m walk, chair stand)

Detailed Description: Arthritis is the most common cause of disability in the United States. Approximately 42.1% of women and 31.2% of men over the age of 60 have knee osteoarthritis (KOA). KOA is associated with pain, quadriceps weakness, swelling, instability, decline of range of motion, physical function, and quality of life (QOL). The presence of KOA significantly decreases QOL, while quadriceps strengthening has the ability to improve QOL. However, one challenge with strengthening is that knee pain influences muscle strength and physical function. Not only quadriceps strengthening but also reduction of knee pain may be necessary to reduce functional limitations from KOA. However, at this time, there is insufficient evidence regarding effective training to not only increase quadriceps strength but also reduce knee pain and improve neural function. Thus, there is a need for interventional studies to build on observational findings to evaluate the relationships of neural function, knee muscle strength, knee pain, and physical function.

The critical barrier to studying whether quadriceps strengthening is protective against worsening physical function is the lack of an effective strengthening program for people at elevated risk for KOA. Factors that place older adults at elevated risk for symptomatic KOA, (e.g. sedentary lifestyle, obesity, knee pain, knee injury or surgery), may also contribute to reduced tolerance of high load quadriceps strengthening programs. If a well-tolerated and effective means of strengthening could be identified, it may also have additional benefits in reducing knee pain, improving physical function and avoiding disability in individuals with or at risk of KOA.

Neuromuscular electrical stimulation (NMES) is widely used to strengthen muscles and improve function in people who cannot exercise at medium-high intensity. For KOA, NMES is effective for enhancing quadriceps strength, knee pain, physical function. Therefore, NMES could contribute to decreased neural inhibition from knee pain and promote muscle function (e.g. muscle strength, power, contraction speed, and co-contraction). Recently, it was reported that the combined application of NMES and volitional contractions (NMES-VC) is effective for making up for a limitation of NMES. NMES-VC could help to improve motor recovery. The results of recent studies suggest that a hybrid training system that utilizes both volitional contractions and NMES simultaneously, might be an effective method that can improve physical function by strengthening muscles and relieving knee pain in people at risk for incident or progressive symptomatic KOA.

This line of research could have a significant positive impact on public health, by leading to the introduction of an inexpensive means of well-tolerated and safe exercise that can be completed in community rehabilitative environments. Successful completion of this initial investigation will enable pursuit of research to determine whether NMES-VC is effective in quadriceps strengthening and pain relief while improving neural function in symptomatic and progressive KOA. Reduction of this primary cause of disability through cost-effective preventive exercise has a high potential to reduce the burden of disease and disablement, thereby improving the quality of life for older adults and significantly reducing the costs to individuals and society.

The specific aim of the proposed research is to assess the efficacy of a twelve-week, efficient and tolerable, low-intensity exercise program with NMES-VC for improving quadriceps strength, knee pain and physical function in women with risk factors for incident symptomatic or progressive KOA. This specific aim will be achieved through a randomized, controlled trial, comparing low intensity exercise with and without NMES-VC. This research is novel in that it will be the first to use a low load regimen that will minimize the potential for adverse loading on the knee joint while still having a high likelihood to lead to clinically meaningful strength gains, pain relief and physical function improvement in older adults at elevated risk for symptomatic or progressive KOA.

Recruitment & Eligibility

Status: COMPLETED

Sex: Female

Target Recruitment: 42

Inclusion Criteria

Female
Age 40-85 years
One or more of the following:
1. Knee symptoms (pain, aching, or stiffness) on most of the last 30 days; categorically defined, so all severity of symptoms ok, but must have knee symptoms on most days
2. History of knee injury or surgery
3. Body Mass Index (BMI) greater than or equal to 25 kg/m2
BMI less than 45 kg/m2

Exclusion Criteria

Knee injection within 6 weeks prior to the study
Resistance training at any time in the last 3 months prior to the study
Bilateral knee replacement
Lower limb amputation
Lower limb surgery in the last 6 months that affects walking ability or ability to exercise
Back, hip or knee problems that affect walking ability or ability to exercise
Unable to walk without a cane or walker
Inflammatory joint or muscle disease such as rheumatoid or psoriatic arthritis or polymyalgia rheumatica
Multiple sclerosis or other neurodegenerative disorder
Known neuropathy
Self-report of Diabetes
Currently being treated for cancer or having untreated cancer
Terminal illness (cannot be cured or adequately treated and there is a reasonable expectation of death in the near future)
Peripheral Vascular Disease
History of myocardial infarction or stroke in the last year
Chest pain during exercise or at rest
Use of supplemental oxygen
Inability to follow protocol (e.g. lack of ability to attend visits or understand instructions)
Staff concern for participant health (such as history of dizziness/faintness or current restrictions on activity)
Unable to attend 12 or more sessions during the study
Implanted cardiac pacemaker, spinal cord stimulator, baclofen or morphine pump or other implanted electrical device.
Dermatitis or skin sensitivity.
Pregnancy

Study & Design

Study Type: INTERVENTIONAL

Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Hybrid Training	Hybrid Training using Electrodes and Joint Motion Sensors	The hybrid training system combines the applications of neuromuscular electrical stimulation (NMES) with voluntary contractions (NMES-VC). Training will be performed in a seated position with feet not touching the ground, and will involve each knee flexing and extending alternately. The joint range of motion will be restricted to a 90º arc from approximately 10º to 100º of flexion. Each session will consist of 5 sets of 10 repetitions, 3-second knee flexion and extension contractions on each leg. Sets will be separated by 30-sec rest intervals. Electrodes will be placed on the anterior thigh over the motor points of the bilateral vastus medialis and lateralis, and over the medial and lateral hamstrings on the posterior thigh. Electrical stimulation intensity will be set to approximately 40% of 1 repetition maximum (RM). A joint motion sensor will trigger stimulation of the antagonist once it senses the initiation of volitional contraction of the agonist muscle group.
Low Intensity Exercise	Isokinetic Training with Isokinetic Dynamometer	40% 1-repetition maximum isokinetic training with HUMAC NORM in same repetitions/sets as experimental group.

Primary Outcome Measures

Name	Time	Method
Change in Maximal Isokinetic Knee Extensor Torque by Body Mass Assessed by Isokinetic Dynamometer.	Baseline and 12-week follow-up	Participants will be familiarized with strength testing equipment and counseled on proper lifting technique. They will undergo testing to determine their peak isokinetic knee extensor torque at 60°/sec, using an isokinetic dynamometer. These testing procedures will then be repeated for the other side.

Secondary Outcome Measures

Name	Time	Method
Change in Maximal Isokinetic Knee Flexor Torque by Body Mass Assessed by Isokinetic Dynamometer.	Baseline and 12-week follow-up	Participants will be familiarized with strength testing equipment and counseled on proper lifting technique. They will undergo testing to determine their peak isokinetic knee flexor torque, using an isokinetic dynamometer.
Change in Knee Pain Assessed by a Knee Injury and Osteoarthritis Outcome Score	Baseline and 12-week follow-up	The Knee Injury and Osteoarthritis Outcome Score (KOOS) Pain subscale was used at baseline and follow-up to assess participant outcomes. The pain subscale is made up of 9 questions and was scored from zero to 100, with zero corresponding to extreme knee problems and 100 corresponding to no knee problems.
Change in 20-meter Walk Time	Baseline and 12-week follow-up	A timed 20-meter walk was completed as a measure of lower limb physical performance. Participants were instructed to walk along a 20-meters straight, uninterrupted course as quickly as they could. Timing started when the participant initiated foot movement and stopped when both feet crossed the 20-meter mark. Times for two trials were recorded and the averaged.
Change in 5-chair Stand Time	Baseline and 12-week follow-up	The chair stand test is a validated measure of physical performance in adults with knee osteoarthritis. Participants were instructed to stand from a chair (seat height 44.45 cm) 5 times as quickly as they could without using their arms. Two trials were timed and averaged.