Accessibility navigation

Effects of a web-based personalized intervention on physical activity in European adults: a randomized controlled trial

Marsaux, C. F. M., Celis-Morales, C., Fallaize, R., Macready, A. ORCID:, Kolossa, S., Woolhead, C., O'Donovan, C. B., Forster, H., Navas-Carretero, S., San-Cristobal, R., Lambrinou, C.-P., Moschonis, G., Surwillo, A., Godlewska, M., Goris, A., Hoonhout, J., Drevon, C., Manios, Y., Traczyk, I., Walsh, M. C. , Gibney, E. R., Brennan, L., Martinez, J. A., Lovegrove, J. ORCID:, Gibney, M. J., Daniel, H., Mathers, J. C. and Saris, W. H. M. (2015) Effects of a web-based personalized intervention on physical activity in European adults: a randomized controlled trial. Journal of Medical Internet Research, 17 (10). e231. ISSN 1438-8871

Text - Accepted Version
· Please see our End User Agreement before downloading.


It is advisable to refer to the publisher's version if you intend to cite from this work. See Guidance on citing.

To link to this item DOI: 10.2196/jmir.4660


Background: The high prevalence of physical inactivity worldwide calls for innovative and more effective ways to promote physical activity (PA). There are limited objective data on the effectiveness of Web-based personalized feedback on increasing PA in adults. Objective: It is hypothesized that providing personalized advice based on PA measured objectively alongside diet, phenotype, or genotype information would lead to larger and more sustained changes in PA, compared with nonpersonalized advice. Methods: A total of 1607 adults in seven European countries were randomized to either a control group (nonpersonalized advice, Level 0, L0) or to one of three personalized groups receiving personalized advice via the Internet based on current PA plus diet (Level 1, L1), PA plus diet and phenotype (Level 2, L2), or PA plus diet, phenotype, and genotype (Level 3, L3). PA was measured for 6 months using triaxial accelerometers, and self-reported using the Baecke questionnaire. Outcomes were objective and self-reported PA after 3 and 6 months. Results: While 1270 participants (85.81% of 1480 actual starters) completed the 6-month trial, 1233 (83.31%) self-reported PA at both baseline and month 6, but only 730 (49.32%) had sufficient objective PA data at both time points. For the total cohort after 6 months, a greater improvement in self-reported total PA (P=.02) and PA during leisure (nonsport) (P=.03) was observed in personalized groups compared with the control group. For individuals advised to increase PA, we also observed greater improvements in those two self-reported indices (P=.006 and P=.008, respectively) with increased personalization of the advice (L2 and L3 vs L1). However, there were no significant differences in accelerometer results between personalized and control groups, and no significant effect of adding phenotypic or genotypic information to the tailored feedback at month 3 or 6. After 6 months, there were small but significant improvements in the objectively measured physical activity level (P<.05), moderate PA (P<.01), and sedentary time (P<.001) for individuals advised to increase PA, but these changes were similar across all groups. Conclusions: Different levels of personalization produced similar small changes in objective PA. We found no evidence that personalized advice is more effective than conventional “one size fits all” guidelines to promote changes in PA in our Web-based intervention when PA was measured objectively. Based on self-reports, PA increased to a greater extent with more personalized advice. Thus, it is crucial to measure PA objectively in any PA intervention study.

Item Type:Article
Divisions:Interdisciplinary centres and themes > Food Chain and Health
Interdisciplinary Research Centres (IDRCs) > Centre for Integrative Neuroscience and Neurodynamics (CINN)
Life Sciences > School of Agriculture, Policy and Development > Department of Agri-Food Economics & Marketing
Life Sciences > School of Chemistry, Food and Pharmacy > Department of Food and Nutritional Sciences > Human Nutrition Research Group
Life Sciences > School of Psychology and Clinical Language Sciences > Nutrition and Health
ID Code:44564
Uncontrolled Keywords:physical activity; eHealth; randomized controlled trial; personalized nutrition; genotype; phenotype; Internet
Publisher:JMIR Publications
Publisher Statement:Copyright ©Cyril FM Marsaux, Carlos Celis-Morales, Rosalind Fallaize, Anna L Macready, Silvia Kolossa, Clara Woolhead, Clare B O'Donovan, Hannah Forster, Santiago Navas-Carretero, Rodrigo San-Cristobal, Christina-Paulina Lambrinou, George Moschonis, Agnieszka Surwillo, Magdalena Godlewska, Annelies Goris, Jettie Hoonhout, Christian A Drevon, Yannis Manios, Iwona Traczyk, Marianne C Walsh, Eileen R Gibney, Lorraine Brennan, J Alfredo Martinez, Julie A Lovegrove, Michael J Gibney, Hannelore Daniel, John C Mathers, Wim HM Saris. Originally published in the Journal of Medical Internet Research (, 14.10.2015. This is an open-access article distributed under the terms of the Creative Commons Attribution License (, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work, first published in the Journal of Medical Internet Research, is properly cited. The complete bibliographic information, a link to the original publication on, as well as this copyright and license information must be included.


Downloads per month over past year

University Staff: Request a correction | Centaur Editors: Update this record

Page navigation