Using test dummy experiments to investigate pediatric injury risk in simulated short-distance falls

Background: Short-distance falls, such as from a bed, are often falsely reported scenarios in child abuse. In attempting to differentiate between abusive and nonabusive injury, knowledge of factors that affect injury risk in falls could prove useful. Objectives: To assess the biomechanics associated with simulated short-distance falls in children (one fall scenario, without attempting to maximize injury potential) and to investigate the effect of impact surface type on injury risk. Methods: Repeatable fall experiments from bed height (0.68 m) onto different surfaces were conducted using an instrumented side-lying Hybrid II 3-year-old test dummy. Biomechanical measures assessed in falls included head acceleration, pelvis acceleration, femur loading, and head injury criteria. Results: Fall dynamics resulted in the pelvis or legs making first contact. Biomechanical measures assessed in simulated bed falls were below known head injury criteria and lower extremity injury thresholds. The impact surface type had a significant effect on head injury risk and lower extremity loading. Playground foam proved to have the lowest associated injury risk of all the tested surfaces. Conclusions: The biomechanics of a child falling from a short distance, such as from a bed, were investigated using an experimental laboratory mock-up and an instrumented test dummy. Despite the impact surface having an effect on injury risk, rolling from a 0.68-m (27-in) horizontal surface from a side-lying posture presented low risk of contact-type head injury and leg injury on all tested impact surfaces.