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The application of a single three-minute session of muscle energy technique to the lumbosacral joint resulted in decreased motor excitability in the motor cortex and spinal cord, according to recent research.
The study, "The effect of muscle energy technique on corticospinal and spinal reflex excitability in asymptomatic participants," involved 12 healthy volunteers with a mean age of about 26 years and without any current low-back pain. Each of these subjects received a control intervention and then the muscle energy technique intervention, with a five-minute rest period between the two.
For the control intervention, participants were assisted by an osteopath into the lateral recumbent position and remained in this position for approximately three minutes. For the muscle energy technique intervention, the technique was applied to the L5/S1 segment in both left and right lateral recumbent positions, which took about three minutes total.
To perform the muscle energy technique, the subject's hips were in approximately 20 degrees of flexion, the lower left leg was straight and the upper right leg was flexed slightly.
"The upper body was rotated to the right until localization of motion was palpated at L5-S1. The osteopath then manually contracted the tissues overlying the zygopophyseal joint, reinforcing both the lower and upper body rotations," state the study's authors. "After the osteopath verified that the participant was relaxed and tissue tension was maximized to localize the leverage to the joint, the participant produced a moderate isometric rotary force that was resisted
Next, the subject relaxed and the osteopath increased the lumbosacral rotation until the new physiological barrier was engaged, and three repetitions of resistance, relaxation and re-engagement of the barrier were performed. The procedure was then repeated on the right side.
Outcome measures for this study were compound muscle action potentials (M-waves) and Hoffman reflexes (H-reflexes) testing, motor evoked potentials (MEPs) and silent periods (SPs). These measures are reported to allow researchers to assess motor excitability in the motor cortex and spinal cord. These outcome measures were recorded before and after the control intervention, and then again after the muscle energy technique intervention.
"MET applied bilaterally to the L5/S1 of segment asymptomatic participants produced significant reductions in motor neuron excitability," state the study's authors. "Increases in the SP duration of the MEP waveform, and reductions in H-reflex amplitude, demonstrate that [muscle energy technique] produces an immediate inhibition of motor neuron excitability in the motor cortex and the spinal cord."
Authors: Gary Fryer and Alan J. Pearce.
Sources: College of Health & Biomedicine, Institute of Sport, Exercise & Active Living, Victoria University, Melbourne, Australia; Cognitive and Exercise Neuroscience Laboratory, School of Psychology, Deakin University, Melbourne, Australia; and A.T. Still Research Institute, Kirksville, Missouri. Originally published in 2013 in the Journal of Bodywork & Movement Therapies, 17, 440-447.