Understanding how repeated head impacts (RHI) affect the developing brain - along with the biological, behavioral, and social factors that influence short- and long-term exposure - is a growing area of scientific inquiry and public health concern. The National Academies' Forum on Traumatic Brain Injury convened a workshop in April 2025 to examine the known and unknown surrounding youth exposure to RHI.Discussions addressed definitions and measurement of RHI, strategies to minimize RHI exposure across youth sports and other settings, and evidence on short- and long-term outcomes, noting that substantial gaps remain. Speakers highlighted the need for better standardization in measurement methods; long-term studies using validated, multimodal measures and more inclusive research across diverse activities and populations; and stronger communication between researchers, clinicians, families, and communities. This Proceedings of a Workshop summarizes presentations and discussions that took place during the event.
