The human musculoskeletal biomechanics lab focuses on the mechanical behaviors of the active neuromuscular and the passive musculoskeletal systems in the human body, and aims at controlling and managing musculoskeletal disorders. A primary area of current research in the lab is the biomechanics of the human trunk as it relates to low back pain. Using both in-vivo experiments and numerical simulations, we examine the effects of personal (e.g., age and physical fitness), physical (e.g., manual handling and vibration) and psychosocial (e.g., stress) risk factors for low back pain on the mechanical behaviors of the active and passive tissues in the human trunk. Also of interest are the effects of different treatment modalities (e.g., physical activity, exercise, manual therapies, and etc) for low back pain. Trunk kinematics and kinetics as well as muscle activities are collected during active (voluntarily and involuntarily) and passive trunk movements using both standard gait lab measuring instruments and custom-designed and fabricated experimental hardware. Obtained data are then input to several mathematical and/or mechanical models (e.g., finite element models, system identification models) to generate a comprehensive set of outcome measures describing the mechanical state of the human trunk. This information provides an estimate of mechanical risk of low back pain due to abnormal mechanics of the trunk; such abnormal mechanics can lead to excessive spinal loading and spinal instability, and we have particular interest in identifying and understand these injury mechanisms and pathways. What we learn has future application for controlling the level of exposure to low back pain risk factors in daily life and at work and potentially as biomarkers for assessing risk and developing/tracking treatment protocols.