Toward Evidence-Based Smartphone Apps to Enhance Human Health: Adoption of Behavior Change Techniques

Criterion Validity of iOS and Android Applications to Measure Steps and Distance in Adults

The growing popularity of physical activity (PA) applications (apps) in recent years and the vast amounts of data that they generate present attractive possibilities for surveillance. However, measurement accuracy is indispensable when tracking PA variables to provide meaningful measures of PA. The purpose of this study was to examine the steps and distance criterion validity of freeware accelerometer-based PA smartphone apps, during incremental-intensity treadmill walking and jogging. Thirty healthy adults (25.9 ± 5.7 years) participated in this cross-sectional study. They were fitted with two smartphones (one with Android and one with iOS operating systems), each one simultaneously running four different apps (i.e., Runtastic Pedometer, Accupedo, Pacer, and Argus). They walked and jogged for 5 min at each of the predefined speeds of 4.8, 6.0, and 8.4 km/h on a treadmill, and two researchers counted every step taken during trials with a digital tally counter. Validity was evaluated by comparing each app with the criterion measure using repeated-measures analysis of variance (ANOVA), mean absolute percentage errors (MAPEs), and Bland–Altman plots. For step count, Android apps performed slightly more accurately that iOS apps; nevertheless, MAPEs were generally low for all apps (<5%) and accuracy increased at higher speeds. On the other hand, errors were significantly higher for distance estimation (>10%). The findings suggest that accelerometer-based apps are accurate tools for counting steps during treadmill walking and jogging and could be considered suitable for use as an outcome measure within a clinical trial. However, none of the examined apps was suitable for measuring distance.

Connecting through Technology: Smartphone Users’ Social Cognitive and Emotional Motivations

Smartphones provide various services not only for social purposes but also for personal desires. This study aims to understand the multi-dimensional motivations of smartphone users. An extended motivational framework was developed using perceived benefits (i.e., expected benefits) and social influence (i.e., social identity achieved from mobile social media) from a social cognitive perspective, which was then expanded to incorporate the second-order construct of emotional attachment (i.e., emotional desires). This study examines the effects of motivations on value perceptions, which consequently explains current smartphone use. Structural equation modeling (SEM) was used, and data collected from 738 current smartphone users were analyzed. Regarding the results, expected benefits (i.e., information seeking, entertained activity, self-reactiveness, and immediate access), social influence (i.e., social identity achieved from mobile social media), and emotional desires (i.e., emotional attachment) explained value perceptions (i.e., social, hedonic, and utilitarian values) which positively influence the recent use of smartphones.