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.