Transient analysis of trunk response in sudden release loading using kinematics-driven finite element model

Area of Science:

• Biomechanics
• Occupational Health
• Sports Science

Background:

• Sudden trunk perturbations are common in occupational and sports activities.
• Existing research lacks comprehensive modeling of trunk biodynamics during sudden loading/unloading.
• Understanding these dynamics is crucial for injury prevention and performance enhancement.

Purpose of the Study:

• To develop and utilize a comprehensive modeling simulation for trunk biodynamics.
• To investigate the temporal variations in trunk muscle forces, internal loads, and stability.
• To analyze responses before and after a sudden release of a posterior horizontal load.

Main Methods:

• Employed a dynamic kinematics-driven approach for simulation.
• Used measured post-disturbance trunk kinematics as input data.
• Validated model outputs qualitatively with muscle electromyography (EMG) activities.

Main Results:

• Computed muscle forces closely matched reported EMG activities, showing activation latency and reflex responses.
• The trunk demonstrated stability before and in the early period after load release.
• Increased load magnitude significantly amplified trunk kinematics, muscle forces, and spinal loads.

Conclusions:

• High spinal loads from muscle forces during sudden loading are a risk factor, exacerbated by larger perturbations and longer latencies.
• The central nervous system's reflexive control attempts to manage disturbances, but can be overwhelmed.
• The developed kinematics-driven model shows potential for applications in ergonomics, training, and rehabilitation programs.