A Randomized-Controlled Lifestyle Intervention to Increase Physical Activity Levels in Adolescents

Overview

Students at the age of 14-16 years will be randomized to one intervention arm or one control arm in a 1:1 ratio. Participants of both groups receive a fitness tracker to count the amount of their steps taken. The participants of the intervention arm will commit themselves to a personal goal of steps taken by means of a commitment contract. Achievement of the goal will be rewarded with financial incentives to fulfill the requirements of proper reward medium, according to the Induced Value Theory (Smith, 1976). The duration of the intervention will be 1 year; incentives are provided for 6 months, the remaining 6 months are the follow-up period. The hypothesis is that intensified motivational strategies like the provision of commitment contracts and nudges are effective in increasing the number of steps taken per month compared to a control group.

Adolescents age 14 to 16 years visiting schools throughout Tyrol, Austria will be randomized to one intervention arm or a control arm on a class-wise level in a 1:1 ratio. Participants will be invited by the Department of Education in Tyrol and schools will be contacted directly. At the baseline examination cardiovascular risk profiles (including laboratory analysis; anthropometry; a standardized medical interview; and blood pressure, bioelectrical impedance and pulse-wave velocity measurements) are determined and results are communicated in an individual discussion of results. Afterwards, participants of both groups receive a fitness tracker to count the amount of their steps taken. The participants of the intervention arm will commit themselves to a personal goal of steps taken by means of a commitment contract. Achievement of the goal will be rewarded with financial incentives to fulfill the requirements of proper reward medium, according to the Induced Value Theory (Smith, 1976) and nudges (reminders) will be provided to increase motivation. The duration of the intervention will be 1 year; incentives are provided for 6 months, the remaining 6 months are the follow-up period. After 1 year a follow-up examination will be conducted. Economic experiments on time and risk preferences are furthermore carried out at baseline. The hypothesis is that intensified motivational strategies like the provision of commitment contracts and nudges are effective in increasing the number of steps taken per month compared to a control group.