Table 1 Intervention description using the Template for Intervention Description and Replication (TIDieR) checklist [28] for Active Women Over 50 study
 1. Brief name | Active Women over 50 online physical activity information and support |
 2. Why | Physical activity has many physical and mental health benefits, including the delay of developing disability in older age. Yet the uptake of this health behaviour is particularly low in older women and sub-optimal in working women in their middle age. While commencement of regular sufficient physical activity in middle-age years needs to be a priority for healthy ageing, women over 50 years have unique barriers to becoming more active (e.g. higher sedentary time, greater carer responsibilities, work demands). Behavioural interventions delivered remotely and digitally via web, email and SMS platforms offer wide reach and provide flexibility of intervention use at times and location convenient for the user. Telephone health coaching can also be delivered remotely and provides tailoring of the intervention to a person’s abilities and preferences. A theoretical basis incorporating the Behaviour Change Wheel and COM-B system model of behaviour, Social Determination Theory has been used to design the intervention and choice of behaviour change techniques. The intervention targets barriers unique to women over 50 and will incorporate the behaviour change techniques including goal setting, problem-solving, action and coping planning, review of behavioural goals, self-monitoring, social support and social comparison, information provision, persuasion about capability and habit formation to facilitate and sustain behavioural change. |
 3. What materials | Participants will have access to the internet. The website will be accessed by the internet and will provide 1) information for the benefits of physical activity including links specific to women, different health conditions and ages; 2) resources and strategies for how to become physically active including a pre-exercise screening tool and exercise intensity guidelines [29], guide on getting started, internet-based programme resources such as the Active and Healthy website [30], parkrun website promoting free, weekly community walk/runs [31], links to sporting groups and suggestions of smartphone applications; 3) inspirational stories of people becoming physically active including professionally produced video case study interviews of four real-life female women aged over 50 who have overcome barriers to increase their physical activity; and 4) the opportunity for participants to share their own ideas and inspirational stories via the website. Participants will also receive their choice of either 8 email messages or 24 SMS messages embedded with behaviour change techniques that will link back to and reinforce the website content and provide further motivation to increase their physical activity. Participants will also receive one telephone health coaching session with a trained research physiotherapist trained in physical activity behaviour change techniques. |
 4. What procedures | Access to the intervention website will be provided to participants upon randomisation to the intervention group. Participants will be asked not to share the website to avoid contamination. Participants will also be given the choice to receive either 8 emails or 24 SMS messages over the 3-month study period, and a mutually agreed time will be made for the health coach to contact the participants within 2 weeks of receiving access to the intervention. The health coach will document behaviour change techniques used in the telephone session. All participants will have email access to the trial manager for any further enquiries. |
 5. Who provided | The study manager will provide participants with access to the website, regular messages and liaise appointment times with the health coach. Health coaching will be provided by a tertiary-trained physiotherapist employed by the study with research experience delivering telephone-based health coaching. The coach will have completed courses through Wellness Coaching Australia [32], HealthChange Australia [33] and Medicoach [34] in motivational interviewing and behavioural intervention techniques. |
 6. How | Participants will be notified by email upon randomisation to the intervention group and will gain access to the intervention website via a web address. Frequency of accessing the website will be at the discretion of the participant. The email will also give participants the choice to receive regular messages via email or SMS and will ask for available times when the health coach may contact them. The health coach will be provided with participants’ available times, contact, demographic and current physical activity details by the study manager. |
 7. Where | Participants will access the intervention via the internet and telephone at a location of their convenience. |
 8. When and how much | After participants are given the intervention website address, they have access to the website at any frequency they choose. The regular email or SMS messages link back to the website to support behaviour change with the reinforcement of information and suggested strategies. The health coaching telephone call will be made within 2 weeks of accessing the intervention. There will be no cost to participate. |
 9. Tailoring | All participants will receive the same online resource (website and email or SMS messaging content), but the opportunity to talk with a health coach will allow for tailoring to individual’s preferences, needs and circumstances so that physical activity can be adopted and maintained. Participants will be advised to seek individual advice from a health professional if they are concerned about commencing physical activity or have an injury. |