What makes implementation intentions (in)effective for physical activity among older adults?

OBJECTIVES

For most populations, implementation intentions (IIs) facilitate physical activity (PA). However, for older adults, previous studies found mixed evidence for the effectiveness of this behaviour change technique. To examine which characteristics of IIs predict successful enactment, the content of older participants' IIs formed within a self-regulatory intervention to prompt PA was analysed.

DESIGN

A sample of N = 126 German speaking adults aged 64 and older formed up to six IIs for PA and reported their enactment 5 weeks later.

METHODS

Controlling for age and sex, multilevel models tested associations between characteristics of IIs (e.g., chronological rank of II, hetero- and homogeneity, specificity, presence of certain cues) and enactment.

RESULTS

Significantly related to enactment were: the chronological rank of an II (first IIs superior to last IIs), greater heterogeneity in activities, greater specificity of when-cues, and greater use of pre-existing routines.

CONCLUSIONS

Participants were more likely to enact their IIs 5 weeks later if they planned different (heterogeneous) activities, created IIs with more specific when-cues (e.g., on Monday at 9 am), and in particular a routine (e.g., after breakfast). They also enacted the first three IIs (chronological rank of II) more often than the last three IIs. Future experimental studies should test whether providing instructions to create IIs based on the above significant characteristics lead to more effective health behaviour change among older adults.

Habit formation following routine-based versus time-based cue planning: A randomized controlled trial

OBJECTIVES

Habit formation has been identified as one of the key determinants of behaviour change. To initiate habit formation, self-regulation interventions can support individuals to form a cue-behaviour plan and to repeatedly enact the plan in the same context. This randomized controlled trial aimed to model habit formation of an everyday nutrition behaviour and examined whether habit formation and plan enactment differ when individuals plan to enact their behaviour in response to a routine-based versus time-based cue.

DESIGN

Following a baseline assessment, N = 192 adults (aged 18-77 years) were randomly assigned to a routine-based cue or a time-based cue planning intervention, in which they selected an everyday nutrition behaviour and linked it to a daily routine or a time cue.

METHODS

Participants responded to daily questionnaires over 84 days assessing plan enactment and the behaviour's automaticity (as an indicator of habit formation). Multilevel models with days nested in participants were fitted.

RESULTS

As indicated by asymptotic curves, it took a median of 59 days for participants who successfully formed habits to reach peak automaticity. Group-level analyses revealed that both routine-based and time-based cue planning led to increases in automaticity and plan enactment, but no between-condition differences were found. Repeated plan enactment was a key predictor for automaticity.

CONCLUSIONS

Linking one's nutrition behaviour to a daily routine or a specific time was similarly effective for habit formation. Interventions should encourage persons to repeatedly carry out their planned behaviour in response to the planned cue to facilitate habit formation.

What contributes to action plan enactment? Examining characteristics of physical activity plans

OBJECTIVES

Individuals with chronic conditions can benefit from formulating action plans to engage in regular physical activity. However, the content and the successful translation of plans into action, so-called plan enactment, are rarely adequately evaluated. The aim of this study was to describe the content of user-specified plans and to examine whether participants were more likely to enact their plans if these plans were highly specific, viable, and instrumental.

DESIGN AND METHODS

The study presents secondary analyses from a larger behavioural intervention in cardiac and orthopaedic rehabilitation. The content of 619 action plans from 229 participants was evaluated by two independent raters (i.e., qualitative analyses and ratings of specificity) and by participants themselves (i.e., instrumentality and viability). Plan enactment was also measured via self-reports. Multilevel analyses examined the relationship between these plan characteristics and subsequent plan enactment, and between plan enactment and aggregated physical activity.

RESULTS

Participants preferred to plan leisure-time physical activities anchored around time-based cues. Specificity of occasion cues (i.e., when to act) and highly instrumental plans were positively associated with plan enactment. Interestingly, individuals who planned less specific behavioural responses (i.e., what to do) were more likely to enact their plans. Plan enactment was positively associated with aggregated behaviour.

CONCLUSIONS

Interventions should not only emphasize the importance of planning, but also the benefits of formulating specific contextual cues. Planning of the behavioural response seems to require less precision. Allowing for some flexibility in executing the anticipated target behaviour seems to aid successful plan enactment. Statement of Contribution What is already known on this subject? Action planning interventions are efficacious in promoting health behaviour. Characteristics of plan content (i.e., specificity) matter for unconditional behaviour change. Plan enactment (i.e., degree to which plan is followed through) is positively linked to behaviour change. What does this study add? Specificity of occasion cues (i.e., when to act) and highly instrumental plans were positively associated with plan enactment. Individuals who planned less specific behavioural responses (i.e., what to do) were more likely to enact their plans. Planning interventions should focus on specificity of context cues but flexibility of behavioural action.