Playground Surfacing: Sand Reduces Risk of Arm Fractures vs Wood Fiber, Study Says

The study data collected from the school playgrounds for 2.5 years found the arm fracture rate was 4.5 per 100,000 student-months for falls into sand, compared with 12.9 for falls onto wood fiber surfaces.

A randomized study published Dec. 15, 2009 in PloS Medicine concludes that ''granitic sand playground surfaces reduce the risk of arm fractures from playground falls when compared with engineered wood fibre surfaces. Upgrading playground surfacing standards to reflect this information will prevent arm fractures.''

The study -- ''School Playground Surfacing and Arm Fractures in Children: A Cluster Randomized Trial Comparing Sand to Wood Chip Surfaces'' (Howard A, Macarthur C, et al.) was a randomized trial of 37 elementary schools in Toronto, Canada with a total of 15,074 students. Each school received qualified funding for installation of new playground equipment and surfacing.

The authors note that children who fall off playground equipment are nearly four times as likely to break a bone (often the arm) as children who fall from a standing height.

The researchers' finding that wood fiber surfaces (pictured) don't afford as good a cushioning effect as sand may surprise playground specifiers.

The risk of arm fracture from playground falls onto granitic sand versus onto engineered wood fiber surfaces was compared with an outcome measure of estimated arm fracture rate per 100,000 student-months. Schools were randomly assigned by computer-generated list to receive either a granitic sand or engineered wood fiber playground surface. Schools were visited to ascertain the playground and surface installed and to periodically monitor the depth of the surfacing.

Injury data, including details of circumstance and diagnosis, were collected at each school by a prospective surveillance system with confirmation of injury details through a validated telephone interview with parents and also through medical reports of the treated injuries.

Injury data for all the schools were collected for 2.5 years. Among all schools, the arm fracture rate was 4.5 per 100,000 student-months for falls into sand compared with 12.9 for falls onto wood fiber surfaces. No serious head injuries and no fatalities were observed in either group.

The study concluded the ''upgrading playground surfacing standards to reflect this information will prevent arm fractures.''

The study was funded by the Canadian Institutes for Health Research MCT.