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

Objectives: To determine content validity of the Muscle Power Sprint Test (MPST), and construct validity and reliability of the MPST, 10×5 Meter Sprint Test (10×5MST), 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, and private practices.

Participants: A convenience sample of children and adolescents (N=53; 32 boys, 21 girls; age range, 5-19y) with SB who use a manual wheelchair. Participants were recruited through rehabilitation centers, SB outpatient services, pediatric physical therapists, and the BOSK (Association of Physically Disabled Persons and their Parents).

Interventions: Not applicable.

Main Outcome Measures: Construct validity of 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 10×5MST, slalom test, and 1SPT was analyzed by hypothesis testing using Pearson correlation coefficients and multiple regression. For reliability, intraclass correlation coefficients (ICCs) and smallest detectable changes (SDCs) were calculated.

Results: For the MPST, the mean ± SD exercise time of 4 sprints was 28.1±6.6 seconds. Correlations between the MPST and arm-cranking WAnT were high (r>.72, P<.01). Excellent correlations were found between the 10×5MST and slalom test (r=.93, P<.01), while correlations between the 10×5MST or slalom test and MPST and 1SPT were moderate (r=-.56 to -.70; r=.56, P<.01). The variation of the 1SPT was explained for 38% by wheelchair mass (β=-.489) and total upper muscle strength (β=.420). All ICCs were excellent (ICCs>.95), but the SDCs varied widely.

Conclusions: The MPST is a valid and reliable test in wheelchair-using youth with SB for measuring anaerobic performance. The 10×5MST and slalom test are valid and reliable for measuring agility. For the 1SPT, both validity and reliability are questionable.