Introduction

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The Influence Of A Muscle Energy Treatment Session On Trunk Muscle Activity In Participants With Chronic Low Back Pain Brown, Lauren¹; Banks, Heather¹; Mahato, Niladri²; Clark, Brian²³; Walkowski, Steven²³; Thomas, James¹²³ 1School of Rehabilitation and Communication Sciences, Division of Physical Therapy, Ohio University, 2Ohio Musculoskeletal and Neurological Institute,3Department of Biomedical Sciences College of Osteopathic Medicine, Ohio University, Athens, OH • Introduction • The most common type of pain reported by adults in the United States is low back pain which causes dysfunction, disability, and a decline in daily activities (Day & Nitz, 2012). • After an initial incident of acute low back pain, the likelihood of low back pain reoccurrence is 25% within the first year (Stanton et al., 2008). • There are many treatment approaches for low back pain including therapeutic exercise, modalities, mobilization, manipulation and muscle energy. • Muscle energy is defined as a voluntary muscle contraction performed by the patient “in a precisely controlled direction, against a distinctly executed counter force applied by the operator” (Day & Nitz, 2012). • Muscle energy has been shown to be beneficial for decreasing disability and improving function in individuals suffering from acute low back pain when combined with other treatment techniques such as supervised motor control and resistance exercises (Wilson, Payton, Donegan-Shoaf, & Dec, 2003). • Muscle energy is commonly used in clinical practice for the treatment of low back pain, particularly when patients are unable to receive joint manipulations due to precautions or contraindications (Day & Nitz, 2012). However, there is limited evidence regarding muscle energy as a treatment for chronic low back pain. In addition, changes in lumbar motion following a muscle energy technique have not been investigated. • In contrast, other techniques such as mobilization and manipulation have been highly researched regarding the treatment of low back pain and changes in lumbar mobility. • In the physical therapy discipline, one of the main impairments clinicians focus on during the episode of care is decreasing the patient’s pain. In contrast, osteopaths focus more on restoring normal kinematics and motion regardless of the source of the patient’s pain. We chose to focus on changes in lumbar kinematics to understand the effects of muscle energy treatment from a different perspective. • More specifically, the purpose of this study was to examine the influence of a muscle energy treatment session on lumbar flexion during reaching in female subjects with and without chronic low back pain. • Methods • This study was a sub-set of a larger study consisting of reaching tasks and sudden trunk perturbations before and after a muscle energy treatment session was performed. Thirteen subjects with chronic low back pain and twelve healthy subjects were recruited. The subjects were matched on age, height, and weight Prior to testing, subjects completed the Roland Morris Disability Questionnaire (RMDQ) and the McGill Pain Questionnaire-short form (MPQ-SF). To track full body motion, reflective markers were placed on the subjects’ limbs and trunk segments. The trajectories were recorded using Nexus software and a 7-camera Vicon MX-13 system. The 3-D Euler angles of the thoracic and lumbar spines were calculated in Motion Monitor. Muscle activity of the left and right rectus abdominus, external oblique, internal oblique and iliocostalis lumborum were recorded at 1000Hz using a 16 channel Delsys Bagnoli system. The first task consisted of a series of trunk perturbations where the timing and direction were unanticipated, followed by a forward reaching task to two targets (high and low) with both hands. The targets were normalized to the subject’s anthropometric measures, and were located in the mid-sagittal plane and 30° to each side of the subject. The subjects completed 3 trials to each target location, and then received a single muscle energy treatment on the low back. The reaching and perturbations tasks were then repeated in reverse order. Mixed model ANOVAs were used to test the effects of group (LBP and healthy) and treatment (pre and post muscle energy treatment) on the magnitude of lumbar spine excursion used to complete the reaching tasks. Figure 3: Aggregate data displaying subjects’ lumbar excursion during a reaching task. Following treatment, females with LBP demonstrated increased lumbar flexion whereas healthy female subjects exhibited a slight decrease in lumbar flexion. Figure 1: Target heights were calculated using the subject’s anthropometric measurements. Subjects could reach each target location with their shoulder flexed to 90° and elbow extended by flexing the hips 15° or 30°. Results Our healthy subjects had an average score of 0 on the MPQ-SF PPI, whereas the LBP subjects had an average score of 1.33. On the RMDQ, the healthy subjects had an average score of 0, and the LBP subjects had an average score of 5.67. There were no significant differences between the groups for age, height and weight (p>.05). Across the two target locations located in the mid-sagittal plane, the average lumbar excursion was 19.1° for the LBP subjects and 11.4° for the healthy matched controls (SD=2.59, F=4.36, p=.05) There was no significant difference found regarding only the muscle energy technique on lumbar excursion, as well as no difference during reaching requiring 30° of lumbar rotation to each side. On the contrary, there was a significant interaction of treatment (pre vs. post-muscle energy technique) and group (LBP vs. healthy subjects) (F=6.78, p=.02). After treatment, females with LBP demonstrated increased lumbar flexion whereas healthy female subjects exhibited a slight decrease in lumbar flexion. Conclusions We chose to examine a commonly used clinical technique which currently does not have a sufficient level of supportive evidence for its usefulness in the treatment of low back pain. The evidence that currently exists focuses on using muscle energy to relieve the patient’s pain as opposed to its use to improve the kinematics at that area. Our research shows that there is support for the use of muscle energy to improve lumbar excursion. Specifically, female subjects with low back pain displayed increased lumbar flexion motion in a reaching task after receiving the muscle energy treatment. Healthy female subjects showed slightly less lumbar flexion following the same treatment. Females with chronic low back pain may benefit from muscle energy treatment to improve lumbar motion as well as their ability to perform tasks requiring large trunk excursions. • Future Directions • Following muscle energy treatment, do subjects report less pain and disability with performance of ADL’s? • Would repeated muscle energy treatments have the same effect on lumbar excursion? • How long do the effects of a single muscle energy treatment last? • Are similar results found with male subjects undergoing the same treatment? • We chose not to analyze the EMG data for our study. However, this could be an area of focus in future investigations. • References • Day, J.M., Nitz, A. J. (2012). The Effect of Muscle Energy Techniques on Disability and Pain Scores in Individuals With Low Back Pain. Journal of Sport Rehabilitation, 194-198. • Stanton, T.R., Henschke, N., Maher, C. G., Refshauge, K. M., Latimer, J., & McAuley, J. H (2008). After an Episode of Acute Low Back Pain, Recurrence Is Unpredictable and Not as Common as Previously Thought SPINE, Volume 33, 2923-2928. • Wilson, E., Payton, O., & Donegan-Shoaf, L., Dec, K. (2003). Muscle Energy Technique in Patients with Acute Low Back Pain: A Pilot Clinical Trial. Journal of Orthopaedic & Sports Physical Therapy, volume 33, 502-512. Figure 2: A subject is depicted performing the reaching task.