Method: . Seven adolescents with visual impairments (1 female, 6 male; ages 14-17) were recruited from a Midwestern school for the blind. Visual impairment was categorized as B1 (n=1), B2, (n=5), or B3 (n=1) as per the USABA (2004) sport classifications. The AP selected for this study was the Centrios talking pedometer (Orbyx Electronics, model 6310620, Concord, Canada), which has been previously validated in clinical settings. The criterion pedometer (CP) chosen was the Digi-Walker SW-200 (Yamax, Tokyo, Japan) because of its reputation as a “gold standard” for measuring physical activity in field settings (Brusseau et al., 2011). Both pedometers were attached to an elastic belt. Participants wore the belt along the waistband and devices were placed on the anterior midline of the thigh across from their mobility aids (e.g., long cane). Data were collected over two, 210 minute sessions. Five participants wore the pedometers during both sessions, whereas two participants wore the pedometers for one session. Therefore, 12 data points were obtained.
Analysis/Results: AP step counts ranged from 710-9,414 per session (M=3,714). CP step counts ranged from 645-9,234 (M=3,495). Data were analyzed using percent difference (PD= [(criterion pedometer-audio pedometer)/ audio pedometer] x 100). Mean percent difference across 12 data points was 6.1% (range, 9.7% - 1.0%). A Pearson product moment bivariate correlation determined that both pedometers were highly correlated, r(10) =.998, p<.01.
Conclusions: Schneider and colleagues (2004) report that difference scores within 10% of criterion, are appropriate for free-living conditions. Results are below the 10% threshold, and are more accurate than APs results reported in previous free-living condition research (Albright & Jerome, 2011). Therefore, this study provides validity evidence supporting the use of the Centrios AP for free-living conditions for individuals with visual impairments.