Introduction Chronic respiratory disease (CRD) is associated with reduced physical activity (PA), which pulmonary rehabilitation (PR) can improve. There are a variety of devices which monitor PA. Activity monitors (AM) are relatively small devices which utilise several accelerometers, temperature sensors and the galvanic skin response to provide data regarding energy expenditure, metabolic equivalents and step counts. However, AM's are expensive compared to pedometers and do not provide instant feedback. Our aim was to assess the reliability of step counting by pedometers and AM's compared to visual counts at varying walking speeds in patients with CRD.
Methods 48 patients with CRD wore a Yamax pedometer and a Sensewear Pro3 AM during an ESWT as part of their PR discharge assessment. Speeds were calculated from ISWT and patients had performed the ESWT at baseline, in line with standardised guidelines. Patients requiring walking aids were excluded. Step counts were measured by the pedometer, AM and visually by a separate assessor. Visual step counts were considered “gold-standard” for comparison. For analysis, average step counts for 1 min were calculated at slow, medium and fast speeds. A Friedman's ANOVA test with post-hoc Wilcoxon signed rank was used to compare visual step counts to the pedometer and AM, as the data were not normally distributed.
Results The Friedman's ANOVA demonstrated there was a significant difference between the pedometer, AM and visual step counts at slow (p=0.0001) and medium (p=0.009) speeds but not at fast speeds (p=0.174). Abstract P142 table 1 demonstrates where the differences are between the pedometer, AM and visual step counts from the Wilcoxon signed rank test.
Conclusions At slow and medium walking speeds, there was a significant difference between visual counts and the pedometer and AM. There was also a significant difference between the AM and pedometer at slow speeds. At fast walking speeds there was no significant difference between the visual, pedometer and AM step counts. Overall, both the pedometer and AM underestimated steps at slow and medium walking speeds and are therefore not be suitable for use in patients with CRD who often walk slowly.