Nonlinear System Identification Applied to the Biomechanical Response of the Human Trunk during Sudden Loading

Abstract

Epidemiological and biomechanical studies have indicated that sudden loading of the trunk may be a risk factor for low back pain development. Sudden loads may contribute significantly to the development of low back pain, due to the large muscular force responses associated with these loads. To date, most sudden loading studies have been observational studies that provide rich informational content, but do not provide a solid theoretical model to investigate kinematic and kinetic responses. A novel approach using nonlinear system identification and a time-varying model is introduced in this study to investigate the underlying dynamics of the trunk biomechanical system during sudden loading. This model has been used to study the effects of warning signals, muscular fatigue, and training on the biomechanical response of one subject. Data from this subject and additional subjects may provide recommendations for training protocols and administrative and engineering interventions that minimize exposure to potentially hazardous sudden loads.