BackgroundObesity is a global epidemic. Behavioral change approaches towards improving nutrition, increasing physical activity level, improving sleep, and reducing sitting time are recommended as best practices in adolescent obesity management. However, access to evidence-based treatment is limited and portable technologies such as mobile apps may provide a useful platform to deliver such lifestyle interventions. No evidence-based validated app exists for obesity intervention; therefore, a novel mobile app (Reactivate) was developed for use in the Temple Street W82GO Healthy Lifestyles Program (W82GO).ObjectiveThis study aimed to test the usability (technical effectiveness, efficiency, and user satisfaction) of the Reactivate mobile app in obese adolescents.MethodsTen adolescents (7 males and 3 females, aged 12-17 years) who had been treated for obesity (>98th percentile for body mass index) at the Temple Street Children's University Hospital were recruited. Participants were given 8 tasks to complete in order to test the technical effectiveness of the app. A research assistant timed the user while completing each task in order to test the relative user efficiency of the app (time-on-task). The tasks fell into 5 categories and required the user to enter personal settings, find and answer surveys, create a message, use the goal setting feature, and enter details regarding their weight and height. In exploration of user satisfaction, each participant completed the standardized software usability measurement inventory (SUMI), which measures 5 aspects of user satisfaction: efficiency, effect, helpfulness, controllability, and learnability. Descriptive statistics were used to explore the mean relative user efficiency and SUMI scores.ResultsMean age was 14.26 (SD 1.58) years. All adolescents completed each of the tasks successfully. The mean relative user efficiency scores were two to three times that of an expert user. Users responded that they would use Reactivate to monitor their growth over time, for motivation, and for goal setting. All users described Reactivate as an important mobile app.ConclusionsOur study describes the usability of a mobile app used in adolescent obesity management. Adolescents found Reactivate easy to use and their SUMI results indicated that the app scored high on user satisfaction. Usability testing is an important step towards refining the development of the Reactivate app, which can be used in the treatment of obesity. The study on the clinical efficacy of the Reactivate app is currently underway.

Relevance: This paper presents the results of a research study carried out with the intention to inform physiotherapists on the optimal duration of cold therapy at the ankle in order to maximise the impact on practice of decisions by physiotherapists for their patients/clients.Purpose: The major reason for doing this study was to determine the appropriate duration of ice applications to the ankle joint within the context of skin surface temperature in order to guide physiotherapists to make informed decisions on optimal duration. The aim of this study was to measure skin surface temperature changes at the ankle over a period of time and the objective to determine that point when no more significant skin surface temperature change was recorded.Methods/analysis: An experimental approach was followed to collect skin surface temperature data at the ankle joint, involving a control. Ice application was administered via two standardised methods: an ice bag containing 750 ml of ice cubes and 250 ml of water to 41 participants; and local immersion in a water bath kept between 16 and 18 • C (Lee and Warren, 1978) to 38 participants, who were all recruited through an open call for participation amongst university undergraduate students. The cold modality was applied to the participants' right ankle for 30 minutes, during which skin surface temperature was recorded at 5-minute intervals using the FLIR i3 ® thermal imaging device. Concurrently temperature was recorded at the left ankle that served as a control. Skin surface temperature was recorded every 5 minutes and for a further 20 minutes following removal of the application. Repeated measures analyses of variance were applied to determine the significance of variation in temperature across time whilst pairwise comparisons were examined using post hoc Bonferroni tests.Results: Significant decreases in temperature were obtained for participants undergoing the ice bag