Tailored Multicomponent Intervention for Remote Physical Activity Promotion in Inactive Adults

Physical inactivity (PI) adversely affects various non-communicable diseases (WHO, 2010) and has been recently entitled "the biggest public health problem of the 21th century" (Blair, 2009). Despite the strong evidence for physical activity (PA) related health benefits, one third of the world's population is physically inactive (Hallal et al., 2012). In Switzerland, 35% of the adults are not meeting the minimum recommendation of 2.5h moderate to vigorous activity per week (BASPO, 2013). Present PI patters accompanied with demographic changes and the burden of non-communicable diseases (WHO, 2010) constitute a notable challenge to the health-care system. Thus, effective prevention programs that engage individuals to become more physically active are needed and of public interest.

Regarding the application for a wide public, the use of technologies for a remote delivery of PA promotion programs is promising (Castro & King, 2002). Thereby, PA lifestyle interventions including individually tailored program components (Noar, Benac, & Harris, 2007), personal coaching (Foster, Richards, Thorogood, & Hillsdon, 2013), behavior change techniques (BCT) (Michie, Abraham, Whittington, McAteer, & Gupta, 2009) and regular prompting (push notifications) (De Leon, Fuentes, & Cohen, 2014) are regarded as effective means to improve PA behavior. However, it is still not examined to date, which intervention components could be effectively translated into practice. The required density, the most effective modality and long-term outcomes of PA promotion program need to be examined (Foster et al., 2013).

Within this study three versions to communicate an individually tailored PA promotion program will be compared. The program consists of individual counseling but is delivered without face-to-face contact. Exercise recommendations and behavior change techniques will be elaborated on an individual basis, communicated and assessed. The programs content will then be tailored according to personal background information (e.g. goals, preferences) assessed by questionnaires.

A personalized activity-profile on a specifically developed internet portal (on www.movingcall.com) enables safe exchange between participant and coach. The activity-profile includes a weekly activity plan, questionnaires and a diary to document daily PA behavior.

All enrolled participants will have access to a personal activity profile and receive a tailored advice to increase their physical activity levels. Depending on the interventional arm the advice will be delivered in a more supportive and interactive manner. Participants will be randomly assigned to one of the three study arms.

The primary objective is to assess the effect of regular coaching and prompting on PA level. Secondary objectives are the assessment of follow-up effects of PA changes and changes in psychosocial determinants of PA as well as the comparison self-reported and objectively assessed PA data.

Outcome measures will be assessed prior to the start of the intervention, at the end of the six months and in the follow-up period after 12 months.