This study will evaluate the acute effects of vibration (whole body vibration and local muscle vibration) on quadriceps function, knee joint proprioception, and gait biomechanics linked to osteoarthritis development in individuals with anterior cruciate ligament reconstruction. Subjects will be randomly assigned to control (no vibration), whole body vibration, and local muscle vibration groups, and the aforementioned characteristics will be assessed prior to and following the respective interventions.
Quadriceps muscle dysfunction and proprioceptive deficits following knee injuries alter walking gait biomechanics in manners that contribute to development of knee osteoarthritis. Current rehabilitation techniques are minimally effective for addressing these complications and preventing knee osteoarthritis. Anterior cruciate ligament reconstruction dramatically increases the risk of knee osteoarthritis, and represents an ideal model for evaluating novel rehabilitation techniques for preventing knee osteoarthritis. Direct (local muscle vibration) and indirect (whole body vibration) vibratory stimuli enhance quadriceps function and proprioception, and may improve rehabilitation and reduce the risk of knee osteoarthritis. The purpose of this investigation is to determine and compare the acute effects of whole body vibration and local muscle vibration on quadriceps function, knee proprioception, and gait biomechanics in individuals with anterior cruciate ligament reconstruction. The investigators hypothesize that vibratory stimuli will enhance quadriceps function, knee proprioception, and gait biomechanics in manners that would reduce the risk of developing knee osteoarthritis, and that whole body vibration and local muscle vibration will produce equivalent improvements in these characteristics.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
SINGLE
Enrollment
75
Neuromuscular Research Lab, University of North Carolina at Chapel Hill
Chapel Hill, North Carolina, United States
Linear Ground Reaction Force Loading Rate
Change score (Post-Pre) for the ground reaction force during the first 50% of the stance phase calculated as the slope of the vertical ground reaction force time series curve from heelstrike to the first ground reaction force peak. Though a "normal" value has not been established, typical values for the raw scores (i.e. not change scores) range 8.5-9.5 multiples of body weight per second.
Time frame: Prior to and immediately following vibration interventions (within 5 minutes).
Quadriceps Strength
Change score (Post-Pre) for maximal isometric knee extension peak torque in Newton\*meters/kilogram body mass. Though a "normal" value has not been established, typical values for the raw values (i.e. not changes scores) range 1.5-3.5 Newton\*meters/kilogram body mass.
Time frame: Prior to and immediately following vibration interventions (within 10 minutes)
Knee Proprioception
Change score (Post-Pre) for the absolute sagittal plane joint reposition error. This value, measured in degrees, represents the absolute difference between a target knee flexion angle and the angle the subject reproduces, and assesses how well the subject can perceive the position of his/her knee in space. Typical values for the raw scores (i.e. not change scores) range from 0.5 - 5 degrees.
Time frame: Prior to and immediately following vibration interventions (within 5 minutes)
Instantaneous Ground Reaction Force Loading Rate
Change score (Post-Pre) loading rate calculated as the peak of the first time derivative of the vertical ground reaction force time series curve during the first 50% of the stance phase. Though a "normal" value has not been established, typical values for the raw scores (i.e. not change scores) range 50-70 multiples of body weight per second.
Time frame: Immediately prior to and following the interventions (within 5 minutes)
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Peak Internal Knee Extension Moment
Change score (Post-Pre) for the peak internal knee extension moment during the first 50% of the stance phase. This value reflects the internal (i.e. muscle and other soft tissue) response to external loading of the knee joint in the sagittal plane of motion, and is indicative of quadriceps muscle function during walking. Though a "normal" value has not been established, typical values for the raw scores (i.e. not change scores) range 2-4 % body weight x height.
Time frame: Immediately prior to and following the interventions (within 5 minutes)
Peak Internal Knee Valgus Moment
Change score (Post-Pre) for the peak internal knee valgus moment during the first 50% of the stance phase. This value reflects the internal (i.e. muscle and other soft tissue) response to external loading of the knee joint in the frontal plane of motion, and is indicative of medial tibiofemoral joint loading during walking. Though a "normal" value has not been established, typical values for the raw scores (i.e. not change scores) range 2-4 % body weight x height.
Time frame: Immediately prior to and following the interventions (within 5 minutes)