Impact of In-Person and Mobile Exercise Coaching on Psychosocial Factors Affecting Exercise Adherence in Inactive Women With Obesity: 20-Week Randomized Controlled Trial
Authors: Gjestvang Christina , Kalhovde John Magne , Mauseth Tangen Elene , Clemm Hege , Haakstad Lene Annette Hagen 
Published: February 2025

Background
Regular exercise may counteract obesity-related health risks, but adherence is low among individuals with obesity. Personal trainers may positively influence exercise behavior by providing motivational support. Individuals who receive regular exercise coaching are more likely to adhere to their exercise routine, compared with those who exercise individually. However, investing in personalized exercise guidance, such as a personal trainer, can be expensive for the individual. Thus, integrating web-based coaching could be a more economically sustainable option, offering both flexibility and reduced costs compared with in-person coaching only. Yet, research is needed to assess the effect of hybrid models in improving psychosocial factors among women with obesity.

Objective
This 20-week, pragmatic randomized controlled trial aimed to investigate the effect of weekly in-person coaching compared with 2 combinations of in-person and web-based coaching on 5 psychosocial factors in women with obesity (BMI ≥30 kg/m2).

Methods
Participants were invited through Facebook and Instagram advertisements posted by various fitness clubs across rural and urban locations in Norway (7 different counties and 12 different municipalities). Women with low activity (n=188; <150 minutes of moderate-intensity physical activity/week; 42.7, SD 10.5 years; mean BMI of 35.1, SD 6.9 kg/m2) were allocated into 3 groups of in-person coaching—weekly (n=47), twice weekly (n=47), and once monthly (n=47)—and as controls (n=47). Those with twice weekly and once monthly in-person coaching received web-based coaching of 15 minutes during weeks without in-person coaching. Data included background variables, motivation (Behavioral Regulation in Exercise Questionnaire-2), barriers, self-efficacy (The Self-Efficacy Survey), social support (Social Support Questionnaire), and health-related quality of life (36-Item Short Form Health Survey [SF-36]).

Results
A total of 120 (64%) out of 188 participants completed baseline and postintervention assessments. A minor difference was observed in one item of the SF-36, where all intervention groups reported a greater “change in health last year” than the control group (mean difference: 14.2-17.1, 95% CI 2.04-29.5; g=0.79-1.14; P≤.01). No other effects were found on the selected psychosocial factors. It should be noted that controls reported higher intrinsic motivational regulation at baseline than intervention groups (mean difference: 0.43-0.93; P≤.05). All intervention arms exercised more frequently than controls (mean difference: 1.1-1.5; P≤.001), with no differences in weekly exercise frequency between the 3 intervention arms (P=.30).

Conclusions
We found no effects on motivation, barriers, self-efficacy, perceived social support, or other health domains compared with controls. All intervention groups reported a slight improvement in self-perceived health in 1 of the 8 subscales of the SF-36. Combined in-person and web-based coaching may give a minor improvement in self-perceived health in women with obesity. However, the lack of impact on motivation, barriers, and self-efficacy warrants further research.

Trial Registration
ClinicalTrials.gov NCT05792657; https://clinicaltrials.gov/study/NCT05792657