Assessing Muscle Imbalance in the Lower Back using Vibromyogrophy.

摘要

70–85% of all people will have lower back pain (LBP) at some point in their life, with the annual prevalence averaging 30%. Muscle imbalance is one of the major causes of LBP, a phenomenon that occurs when muscles of the back are overdeveloped while the opposing muscles are weak or stretched out from their normal length.;VMG (Vibromyography) technology was developed to provide a convenient non-invasive means for assessing voluntary muscle effort. The purpose of this study is to develop a reproducible algorithm to predict muscle effort for back muscle activities using VMG technology. VMG transducers were placed on both right and left lumbar erector muscles. A dynamometer (Biodex Medical Systems) was used to control the flexion-extension movement of each person while collecting torque, angular displacement, and angular velocity data. Subjects performed 5 repetitions of back extension from 90° to full upright stance. Isotonic tests were performed with varying torque load added onto the dynamometer. Type I, type IIa and type IIb muscle fiber activities were extracted from the VMG recordings using wavelet packet analysis. Multiple linear regression analysis was utilized to identify the relative contributions of the three muscle fiber types in the erectors.;Results obtained in this study show that enhanced VMG analysis is capable of demonstrating the activity of the postural muscle fibers (slow and intermediate fibers) at low loading levels and low speeds, while higher loads result in the recruitment of Type IIb muscle fibers. Further experimentation will involve investigation of the influence of extension velocity on fiber type recruitment.