Evaluating the Let's Move It intervention programme theory for adolescents' physical activity: Theorized psychosocial mechanisms of behavioural changes.

Objectives: Behaviour change theories have extensively been used in health behaviour change interventions and their programme theories. However, they are rarely evaluated in randomized field studies. The Let's Move It intervention targeted various psychosocial constructs to increase adolescents' physical activity.

How does a school-based intervention impact students' social cognitions on reducing sedentary behavior over 14 months?

Despite sedentary behavior being ubiquitous in students and detrimental to health, interventions specifically targeting it are mostly restricted to leisure time screen time reduction. With six weekly sessions alongside a poster campaign and an additional teacher intervention, the Let's Move It trial delivered environmental and psychological strategies to increase physical activity (PA) and reduce sedentary behavior (SB) in vocational schools, an understudied environment for behavioral interventions. Participants in the intervention arm considerably reduced sedentary time post-intervention.

Biofeedback and Digitalized Motivational Interviewing to Increase Daily Physical Activity: Series of Factorial N-of-1 Randomized Controlled Trials Piloting the Precious App.

Background: Insufficient physical activity is a public health concern. New technologies may improve physical activity levels and enable the identification of its predictors with high accuracy. The Precious smartphone app was developed to investigate the effect of specific modular intervention elements on physical activity and examine theory-based predictors within individuals.

A dual process model to predict adolescents' screen time and physical activity.

Objective: Many adolescents report a lack of physical activity (PA) and excess screen time (ST). Psychological theories aiming to understand these behaviours typically focus on predictors of only one behaviour. Yet, behaviour enactment is often a choice between options.

App-based food Go/No-Go training: User engagement and dietary intake in an opportunistic observational study.

Food Go/No-Go training aims to alter implicit food biases by creating associations between perceiving unhealthy foods and withholding a dominant response. Asking participants to repeatedly inhibit an impulse to approach unhealthy foods can decrease unhealthy food intake in laboratory settings. Less is known about how people engage with app-based Go/No-Go training in real-world settings and how this might relate to dietary outcomes.