Validity and Reliability of Skill-Related Fitness Tests for Wheelchair-Using Youth With Spina Bifida

Abstract

OBJECTIVE: To determine content validity of the Muscle Power Sprint Test (MPST) and construct validity and reliability of the MPST, 10x5 Meter Sprint Test (10x5MST), slalom test and one stroke push test (1SPT) in wheelchair-using youth with spina bifida (SB). DESIGN: Clinimetric study SETTING: Rehabilitation centers, SB outpatient services, private practices PARTICIPANTS: A convenience sample of 53 children (5-19 years, 32 boys / 21 girls) with SB who use a manual wheelchair. Participants were recruited in the Netherlands through rehabilitation centers, SB outpatient services, pediatric physical therapists and the BOSK (Association of and by parents of children, adolescents and adults with a disability). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Construct validity of the the MPST was determined by comparing results with the arm-cranking Wingate Anaerobic test (WAnT) using paired t-tests and Pearson Correlation Coefficients, while content validity was assessed using time based criteria for anaerobic testing . Construct validity of the 10x5MST, slalom test and 1SPT was analyzed by hypothesis testing using Pearson Correlation Coefficients and Multiple Regression. For reliability, Intra Class Correlation coefficients (ICC) and smallest detectable changes (SDC) were calculated. RESULTS: For the MPST, mean exercise time of four sprints was 28.1 sec. (±6.6 sec.). Correlations between the MPST and WAnT were high (r>0.72, p<0.01). Excellent correlations were found between the 10x5MST and slalom test (r=0.93, p<0.01), while correlations between the10x5MST or slalom test and MPST and 1SPT were moderate (r=-0.56- -0.70; r=0.56, p<0.01). The 1SPT was explained for 38% by wheelchair mass (Beta -0.489) and total upper muscle strength (Beta 0.420). All ICCs were excellent (ICC>0.95) but the SDCs varied widely. CONCLUSIONS: The MPST, 10x5MST and slalom test are valid and reliable tests in wheelchair-using youth with SB for measuring respectively anaerobic performance or agility. For the 1SPT, both validity and reliability are questionable.