Reliability and validity of data for 2 newly developed shuttle run tests in children with cerebral palsy

Background and Purpose. The purpose of this study was to examine the reliability and validity of data obtained with 2 newly developed shuttle run tests (SRT-I and SRT-II) to measure aerobic power in children with cerebral palsy (CP) who were classified at level I or II on the Gross Motor Function Classification System (GMFCS). The SRT-I was developed for children at GMFCS level I, and the SRT-II was developed for children at GMFCS level II. Subjects. Twenty-five children and adolescents with CP (10 female, 15 male; mean age=11.9 years, SD=2.9), classified at GMFCS level I (n = 14) or level II (n = 11), participated in the study. Methods. To assess test-retest reliability of data for the 10-m shuttle run tests, the subjects performed the same test within 2 weeks. To examine validity, the shuttle run tests were compared with a GMFCS level-based treadmill test designed to measure peak oxygen uptake. Results. Statistical analyses revealed test-retest reliability for exercise time (number of levels completed) (intraclass correlation coefficients of .97 for the SRT-I and .99 for the SRT-II) and reliability for peak heart rate attained during the final level (intraclass correlation coefficients of .87 for the SRT-I and .94 for the SRT-II). High correlations were found for the relationship between data for both shuttle run tests and data for the treadmill test (r=.96 for both). Discussion and Conclusion. The results suggest that both 10-m shuttle run tests yield reliable and valid data. Moreover, the shuttle run tests have advantages over a treadmill test for children with CP who are able to walk and run (GMFCS level I or II).