Entrapment is defined as "any condition which impedes withdrawal of a body or a body part that has penetrated an opening." Many types of gaps can be found on playground equipment that could result in some type of entrapment.

John Preston was an expert on playground safety. He worked with the Consumer Public Safety Commission to publish the Handbook for Public Playground Safety. Preston revised and updated the handbook in order to clarify the different recommendations and keep it current. This handbook has become a very important part of the playground industry and is known by those in the industry as "Preston's Handbook."

Let's Play, a community partnership program created by Dr. Pepper Snapple Group (DPS), has the goal of getting kids and families active outside and to "provide the tools, places and inspiration to help communities increase physical activity." As part of DPS's corporate philanthropic program, ACTION Nation, Let's Play supports Michelle Obama's Let's Move! initiative, believing that obesity can be solved when everyone cooperates and takes responsibility for getting kids active outside.

Involved with Park and Recreation Associations, David Parker has also become a safety inspector for CPSI and NPSI and worked with ASTM on safety issues. David Parker became a Certified Park and Recreation Professional (CPRP) in 1985.