Rebar, A.L.Williams, R.Short, C.E.Plotnikoff, R.Duncan, M.J.Mummery, K.Alley, S.Schoeppe, S.To, Q.Vandelanotte, C.2025-07-092025-07-092025Psychology and Health, 2025; 40(4):550-5700887-04461476-8321https://hdl.handle.net/2440/145796Objective Action planning is a common approach used in physical activity interventions. The aim of this study was to assess the association of frequency, consistency and content of action planning with physical activity behaviour, intention strength and habit strength. Methods and Measures Within a 3-month web-based, computer-tailored physical activity intervention, participants (N = 115; 68.7% female, M age =43.9; range = 22–73 years) could create 6 rounds of action plans for 4 activities each (24 total). Results Consistency of action planning during the intervention was associated with change in physical activity at 9-months, and intention and habit strength at 3-months and 9-months. Frequency of action planning was negatively associated with intention at 3-months and 9-months. The effect of action planning consistency on physical activity behaviour was no longer significant when accounting for change in intention and habit strength. Conclusion Consistency of how, where, when and with whom people plan their physical activity may translate into stronger physical activity habits. Interventions should avoid encouraging making many distinct action plans, but rather encourage stable contexts through consistent action planning.en© 2023 the author(s). Published by Informa UK limited, trading as Taylor & Francis group. This is an open access article distributed under the terms of the creative commons attribution license (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. the terms on which this article has been published allow the posting of the accepted Manuscript in a repository by the author(s) or with their consent.Habit formation; motivation; exercise; behavioural maintenance; implementation intentionsHealth BehaviorHealth PromotionJournal article10.1080/08870446.2023.2241777658257Short, C.E. [0000-0002-4177-4251]