title: Feasibility and safety of a novel in vivo model to assess playground falls in children.
abstract: BACKGROUND
  Falls are the leading cause of nonfatal unintentional injuries among hospitalized children with playground equipment accounting for more than 50%. National standards for playground rung and rail design exist, but there a lack of in vivo models available to test these standards. We developed a novel in vivo model to test rung and rail design. We report the feasibility and safety of the model.
  
  
  METHODS
  A device was built to simulate children hanging onto a playground bar until their hand slips off. This was defined as breakaway strength. The handle unit was mounted on a vertical cable that was mechanically raised and lowered using a linear actuator controlled by the experimenter. The unit was padded and contained a video camera that recorded the posture of the hand during each trial. Breakaway force and torque were recorded as they held onto the handle by LabView software. In addition, standard anthropometrics and grip strength were recorded.
  
  
  RESULTS
  Biomedical engineering approved the device. There were 425 eligible students aged 5 years to 11 years. Of these, 93% (397) participated (212 males and 185 females). Ninety-nine percent (396 of 397) completed all three experimental stations, one declined because of fear. There were no injuries and no falls. Average time to complete the study was 22 ± 0.5 minutes. Ninety-one percent of participants were right handed; the ethnicity was representative of the local area with 79% being white. Mean ± SD height, weight, and body mass index for the 397 participants were 1.28 ± 0.11 m, 28.0 ± 8.12 kg, and 16.31 ± 2.59 kg/m², respectively. Hand size, grip strength, and maximum breakaway force increased with age.
  
  
  CONCLUSIONS
  This model is safe and feasible and maybe a viable method to assess rung and rail design for playgrounds.
authors.affiliation: Section of Pediatric Surgery, Department of Surgery, College of Engineering, University of Michigan, Ann Arbor, Michigan, USA. pehrlich@med.umich.edu
authors.forename: Peter F
authors.initials: PF
authors.lastname: Ehrlich
authors.forename: Justin G
authors.initials: JG
authors.lastname: Young
authors.forename: Sheryl
authors.initials: S
authors.lastname: Ulin
authors.forename: Charles
authors.initials: C
authors.lastname: Wooley
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Armstrong
authors.forename: Bethany
authors.initials: B
authors.lastname: Buschmann
authors.forename: Andrzej
authors.initials: A
authors.lastname: Galecki
authors.forename: James A
authors.initials: JA
authors.lastname: Ashton-Miller
mesh_terms: D000056:Accident Prevention / Q000379:methods*; D000058:Accidental Falls / Q000517:prevention & control*; D000886:Anthropometry; D001698:Biomedical Engineering; D002648:Child; D002675:Child, Preschool; D004867:Equipment Design; D004869:Equipment Safety; D005240:Feasibility Studies; D005260:Female; D018737:Hand Strength; D006801:Humans; D008297:Male; D008962:Models, Theoretical; D010988:Play and Playthings; D012680:Sensitivity and Specificity