title: Maximum hand-rung coupling forces in children: the effects of handhold diameter.
abstract: OBJECTIVE
  To quantify the effect of handhold size (diameter) on the maximum breakaway strength between a hand and handhold for children.
  
  
  BACKGROUND
  Falls from playground equipment are a major cause of childhood injury and death. It is unclear if recommendations for handholds on playground equipment are too broad.
  
  
  METHODS
  Breakaway strength was defined as the maximum quasistatic force that can be exerted on a grasped object before the object is forcibly pulled from the grasp. Hand anthropometry, grip, and breakaway strengths were measured for 397 children between the ages of 6 and 11 years. Three cylindrical handhold diameters were tested.
  
  
  RESULTS
  Breakaway strength was significantly affected by handhold size, gender, and hand dominance. Significant covariate predictors for breakaway strength included grip strength, age, and hand breadth. Breakaway strength was reduced for the largest diameter (3.81 cm) for children of all ages.
  
  
  CONCLUSIONS
  Handhold design factors significantly affect the breakaway strength of children.
  
  
  CONCLUSIONS
  The results can be used as a basis for design recommendations for hand rungs used by children to reliably support their bodyweight.
authors.affiliation: University of Michigan Medical School, CS Mott Children's Hospital 4-495, 1540 E. Hospital Drive, Ann Arbor, MI 48109-4211, 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: Woolley
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Armstrong
authors.forename: Andrzej
authors.initials: A
authors.lastname: Galecki
authors.forename: Shu
authors.initials: S
authors.lastname: Chen
authors.forename: James A
authors.initials: JA
authors.lastname: Ashton-Miller
mesh_terms: D000058:Accidental Falls / Q000517:prevention & control; D001835:Body Weight; D002648:Child; D002675:Child, Preschool; D004867:Equipment Design; D005260:Female; D018737:Hand Strength; D006801:Humans; D008297:Male; D053581:Muscle Strength Dynamometer; D010988:Play and Playthings