Current playground surface test standards underestimate brain injury risk for children

Area of Science:

• Biomechanics
• Injury Prevention
• Human Factors Engineering

Background:

• Playground surface test standards aim to minimize severe injuries.
• Existing standards use simplifications (hemispherical head, linear kinematics, body exclusion) for practicality.
• The impact of these simplifications on injury prediction is not well understood.

Purpose of the Study:

• To evaluate the effect of simplifications on head kinematics and injury prediction across age groups.
• To compare simulation results with and without the inclusion of the human body.
• To assess the influence of playground surface stiffness and impact location on injury metrics.

Main Methods:

• Utilized the finite element human body model PIPER, scaled for seven age groups (1.5 to 18 years).
• Conducted paired simulations, with and without the body, for three surface stiffness levels and three impact locations.
• Analyzed linear and angular head kinematics, skull bone stress, and brain tissue strain.

Main Results:

• Excluding the body had minimal effect on linear kinematics and skull stress.
• Head angular kinematics and brain tissue strain were underestimated when the body was excluded.
• Including the body altered the predicted performance of playground surfaces regarding head angular kinematics and brain strain.

Conclusions:

• Simplifications in playground safety testing can lead to underestimation of head injury risks.
• Inclusion of a biofidelic body and neck is necessary for accurate head kinematics and brain injury prediction.
• Future playground surface test standards should incorporate full body models and angular kinematics-based injury thresholds to enhance brain injury prevention.