1. 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 recurrence 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 counterforce 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. One of the main impairments that physical therapists focus on during the episode of care is decreasing the patient’s pain. In contrast, osteopaths focus 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 subset of a larger study consisting of reaching tasks and sudden trunk perturbations before and after a muscle energy treatment session. Thirteen subjects with chronic low back pain and 12 healthy subjects were recruited. 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. Trajectories were recorded using Nexus software and a 7-camera Vicon MX-13 system (figure 2). The 3-D Euler angles of the thoracic and lumbar spines were calculated with Motion Monitor software. 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. This was followed by a forward reaching task to two targets (high and low) with both hands using the standardized reaching protocol (Thomas & France, 2007). 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 (figure 1). The subjects completed three trials to each target location and then received a single muscle energy treatment on the low back (figure 3). The reaching and perturbations tasks were then repeated in reverse order. Mixed model ANOVAs were completed 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. Results Healthy subjects had an average score of 0 whereas LBP subjects had an average score of 1.33 on the MPQ-SF Present Pain Intensity index. On the RMDQ, healthy subjects had an average score of 0 and 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 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 the muscle energy technique on lumbar excursion during reaching in the sagittal plane and to each side. On the contrary, there was a significant interaction between group (LBP vs. healthy subjects) and treatment (pre vs. post-muscle energy technique) (F=6.78, p=.02) (figure 3). After treatment, females with LBP demonstrated increased lumbar flexion whereas healthy female subjects exhibited a slight decrease in lumbar flexion (figure 5). Conclusions Muscle energy currently does not have a sufficient level of supportive evidence for its usefulness in the treatment of low back pain. Current evidence focuses on using muscle energy to relieve the patient’s pain as opposed to its use to improve the kinematics at that area. This study provides 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 The results of this study were used as preliminary data for the RELIEF study, a large- scale, randomized clinical trial. It is currently being conducted at Ohio University to examine the neurophysiological effects of manipulation, muscle energy, and cold laser on participants with chronic low back pain (www.ohio.edu/RELIEF). 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. Thomas, J.S. & France, C.R (2007). Pain-Related Fear Is Associated With Avoidance of Spinal Motion During Recovery From Low Back Pain. SPINE, volume 32, 460-466. 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 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°. Figure 2: A typical reach to the high target by a healthy participant is illustrated. Figure 5: 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. The Influence of a Muscle Energy Treatment Session on Trunk Muscle Activity in Participants with Chronic Low Back Pain Lauren Brown¹, Heather Banks¹, Niladri Mahato², Brian Clark², ³, Steven Walkowski², ³, James Thomas¹, ², ³ 1 School of Rehabilitation and Communication Sciences, Division of Physical Therapy, Ohio University, 2 Ohio Musculoskeletal and Neurological Institute, 3 Department of Biomedical Sciences College of Osteopathic Medicine, Ohio University, Athens, OH Figure 4: Amount of trunk excursion during the reaching task in the mid-sagittal plane to the A) high target B) low target and C) average of high and low targets. CBA Figure 3: A muscle energy technique was applied to the lumbar spine of a seated participant by our study physician (SW).