BackgroundVery few objective data exist regarding aerobic performance in young people with cerebral palsy (CP). The characterization of aerobic fitness could provide baseline and outcome measures for the rehabilitation of young people with CP.ObjectiveThe objective of this study was to provide reference values for aerobic fitness in a group of children, adolescents, and young adults who had CP and who were classified at Gross Motor Function Classification System (GMFCS) level I or II. Data were collected with 10-m shuttle run tests.DesignThis investigation was a cross-sectional observational study conducted between August 2008 and June 2009.MethodsReference values were established using data from a total of 306 children, adolescents, and young adults who had CP, who were 6 to 20 years old, and who were recruited from 26 rehabilitation centers in the Netherlands, Switzerland, Australia, Canada, and the United States. A total of 211 participants were classified at GMFCS level I (mean age=12.2 years, SD=3.0), and 95 were classified at GMFCS level II (mean age=12.4 years, SD=3.2); 181 were male, and 125 were female. Aerobic fitness was reflected by the level achieved on the 10-m shuttle run tests.ResultsOn the basis of a total of 306 assessments from the 10-m shuttle run tests, 4 reference curves were created.LimitationsThe limitation of this study is the cross-sectional nature of the design.ConclusionsThis study provided height-related reference values for aerobic fitness in children, adolescents, and young adults who had CP, who were 6 to 20 years old, and who were classified at GMFCS level I or II. Generalized additive models for location, scale, and shape were used to construct centile curves. These curves are clinically relevant and provide a user-friendly method for the prediction of aerobic fitness in young people with CP.