Effect of Hamstring Stretching and Neural Mobilization on Range of Motion and Low Back Pain

Overview

This study was designed to answer 3 primary research questions: 1. In adults with low back pain, reduced SLR ROM (Range of Motion) and a positive sensitized SLR (Straight leg raise) test, does neurodynamic mobilization result in greater SLR ROM, pain reduction and perceived improvement than muscle stretching? 2. In adults with low back pain, reduced SLR ROM and a negative sensitized SLR test, does muscle stretching result in greater SLR ROM, pain reduction and perceived improvement than neurodynamic mobilization? 3. In adults with low back and reduced SLR, does neurodynamic mobilization or muscle stretching result in greater SLR ROM, pain reduction and perceived improvement irrespective of the outcome of SLR sensitization? The research hypotheses are threefold: 1. Subjects determined to have nerve-related pain and ROM restrictions by a positive sensitized SLR test would benefit more from neurodynamic mobilization than muscle stretching. 2. Subjects determined to have muscle-related pain and ROM restrictions by a negative sensitized SLR test would benefit more from muscle stretching than neurodynamic mobilization. 3. Subjects would benefit the same from muscle stretching and neurodynamic mobilization when not matched on the outcome of the SLR sensitization.

Potential subjects will sign an informed consent and be evaluated for inclusion in the study. Subjects meeting the inclusion criteria will be asked to complete a form asking questions regarding their demographics, pain history and symptomatology. The form will also include a numeric pain rating scale to determine pain severity, and a standardized questionnaire commonly used in back pain research (i.e., the Modified Oswestry Disability Index). Subjects will then be evaluated for SLR range of motion on the side with the least amount of SLR range of motion using a bubble inclinometer. Subjects will then be randomly assigned to receive a treatment to address hamstring length or a treatment to address sciatic nerve restrictions. A second researcher who is blinded to the results of the data obtained pre-treatment will administer the treatment. Hamstring stretching will consist of positioning the subject's hip in flexion and knee in extension, and holding this position for 30 seconds. This treatment will be repeated 5 times. Nerve mobilization will consist of either momentarily positioning the hip in flexion, the knee in extension and the ankle in dorsiflexion, and then moving the ankle in and out of dorsiflexion at a rate of about 1 - 2 movements per second (theoretically, this should stretch the nerve), or moving the lower leg such that it is first positioned into hip extension and ankle dorsiflexion, and then into hip flexion and ankle plantarflexion (theoretically, this should glide the nerve in its sheath). The choice of technique will be made by the treating therapist. Both treatments should take approximately 4 minutes to complete. Following this intervention, subjects will be re-evaluated for SLR range of motion using a bubble inclinometer by the same researcher who collected the pre-treatment data. During the next visit to physical therapy, this researcher will re-evaluate subjects SLR range of motion, as previously described; and pain, by the numeric pain rating scale.