A group- and smartphone-based psychological intervention to increase and maintain physical activity in patients with musculoskeletal conditions: study protocol for a randomized controlled trial ("MoVo-App").

Interventions designed to increase the level of physical activity are crucial in the treatment of patients with musculoskeletal conditions. The psychological group-based intervention MoVo-LISA based on the Motivation-Volition (MoVo) Process Model has been shown to effectively promote physical activity. The aim of this study is to evaluate whether a MoVo-based app (MoVo-App) subsequent to MoVo-LISA during orthopedic inpatient care can support people to increase and maintain their amount of physical activity. In this parallel-group randomized controlled trial, patients with musculoskeletal disorders will be randomized to either (a) a combination of the group-based intervention program MoVo-LISA to promote physical activity plus the MoVo-App or (b) the group-based intervention program alone without the app. The intervention group will receive the MoVo-App after discharge from inpatient rehabilitation. They receive help to increase and maintain their level of physical activity (initiated by the group program) by tracking their health goals, activity plans, major barriers, and barrier management that were developed during the group-based program. We will recruit 224 initially minimally active participants during orthopedic rehabilitation care. Outcomes are assessed at clinic admission; discharge; 6 weeks; and 3 (post-treatment), 6, and 12 months after discharge (follow-up). The primary outcome is sport activity (active/inactive and minutes of activity) at 6-month follow-up. Secondary outcomes are movement activity, cognitive mediators of behavioral change (e.g., self-efficacy, action planning), and health-related variables (e.g., pain intensity, depression). To evaluate intervention effects, linear mixed effects models (both on intention-to-treat basis with an additional per-protocol analysis) will be conducted with each outcome variable and with time as the within-subjects factor and group as the between-subjects factor, along with all two-way interactions and accounting for covariates as fixed effects. This is the first evaluation of the effectiveness of an app in combination with a face-to-face group intervention to promote physical activity. The approach of using an app in addition to an effective face-to-face intervention program, both based on the MoVo model, might sustain positive intervention effects introduced in routine health care. The trial “A group- and smartphone-based psychological intervention to increase physical activity in patients with musculoskeletal conditions: A randomized controlled trial” is registered at the World Health Organization International Clinical Trials Registry Platform via the German Clinical Studies Trial Register (DRKS), DRKS00014814. Registered on 18 October 2018; URL: https://www.drks.de/drks_web/navigate.do?navigationId=trial.HTML&TRIAL_ID=DRKS00014814.