Combined Application of Electrical Stimulation and Volitional Contractions for Muscle Strengthening and Knee Pain Inhibition (Seated Study)
Condition: Knee Osteoarthritis
MeSH terms: Osteoarthritis; Osteoarthritis, Knee
Study type: Interventional

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.
    

Intervention name(s): Hybrid Training using Electrodes and Joint Motion Sensors; Isokinetic Training with Isokinetic Dynamometer
Intervention type(s): Device; Device
Intervention description(s): Electrodes (Sekisui Plastics Co., Tokyo, Japan) will be placed on the anterior thigh over the motor points of the bilateral vastus medialis and lateralis, and on the posterior thigh over the motor points of the medial and lateral hamstrings. Electrical stimulation intensity will be set to approximately 40% of 1 repetition maximum (RM).
A joint motion sensor (Mutoh Engineering Inc., Tokyo, Japan) will trigger stimulation of the antagonist once it senses the initiation of volitional contraction of the agonist muscle group.; Low intensity exercises completed using isokinetic dynamometer (HUMAC NORM, Computer Sports Medicine Inc. (CSMi), Stoughton, MA) in isokinetic mode at approximately 40%1 RM.
Other intervention name(s): Resistance Training
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Outcomes Assessor)
Primary purpose: Treatment