New Insights into Compliance with a Mobile Phone Diary and Pedometer Use in Sedentary Women

Objectives: The purposes of this study were 1) to determine compliance with a pedometer and mobile phone- based physical activity diary, and 2) to assess concordance between self-reported daily steps recorded and transmitted by a mobile phone and pedometer-measured daily steps in sedentary women.

Methods: In this 3-week pilot clinical study, 41 sedentary women who met all inclusion criteria were recruited from local communities. We asked the participants to wear a pedometer every day and to report their daily steps using a mobile phone diary each night before retiring. In the first week, women were asked to monitor their daily steps (baseline steps). In the second and third weeks, they were asked to increase their steps by 20% from the previous week. Although the pedometer can automatically store the most recent 41 days' performance, the participants were not informed of this function of the pedometer.

Results: Overall compliance was 93.8% with pedometer use and 88.3% with the mobile phone physical activity diary. Bland Altman plots showed that the agreement between self-reported daily steps by mobile phone diary and pedometer-recorded daily steps from week 1 to week 3 was high.

Conclusion: The combination of a pedometer and a mobile phone diary may enhance the quality of self-reported data in clinical studies.