Table 3 App behaviour change scale score [44] for the ‘My Exercise Messages’ app

1. Knowledge and information

  1.1 Does the app have the ability to customise and personalise some features?

1

Customisable features:

- person’s name to personalise messages

- number of weekly exercise sessions (i.e. set a goal of between 1–7 sessions/week)*

- length of program (between 1–24 weeks)*

- selection of an exercise barrier (if low exercise adherence reported) from a defined list triggers a tailored exercise adherence support message (BCT)

  1.2 Was the app created with expertise and/or Does the app provide information that is consistent with national guidelines?

1

Created by researchers at University of Melbourne with expertise in osteoarthritis, exercise and BCTs

Based on clinical practice guidelines that recommend physical activity and exercise for all people with hip/knee OA

  1.3 Does the app ask for baseline information?

0

  1.4 Does the app provide instruction on how to perform the behaviour?

1

Instruction on how to perform exercise is provided in:

- Facilitator messages × 3

- Barrier response messages × 7^†

Instructional tips provided in ‘Benefits of exercise’ information page under the settings tab

Facilitator message: It’s up to you to stay on track with your exercises with a little bit of help from us! People find it useful to make the exercises a priority and do them before starting the busy day. Try doing them first thing in the morning this week and see if it helps you stay on track

‘The exercises aren’t helping’ barrier response message: It sounds like something needs to change. Your exercises may not be challenging you enough to see improvements. This next week step it up, increase the weights or number of repetitions of an exercise

  1.5 Does the app provide information about the consequences of continuing and/or discontinuing behaviour?

1

Information about health consequences is targeted in:

- Facilitator messages × 13

- Barrier response messages × 28^†

Information about exercise consequences (including risks and benefits) provided in ‘Benefits of exercise’ information page under the settings tab

Facilitator message: (name), let’s bust this myth—surgery is not inevitable if you have osteoarthritis! Exercise is one of the most effective ways to reduce your joint pain and prevent surgery

‘My pain limited my ability to do my exercises’ barrier response message: It sounds like your joint’s a bit sore already. Remember with osteoarthritis some days are worse than others. Consider doing a bit of exercise on the days when the pain isn’t as severe. Doing some exercise now could help there be less bad days in the long run

2. Goals and planning

  2.1 Does the app ask for willingness for behaviour change?

0

  2.2 Does the app allow for the setting of goals?

1

Setting of weekly exercise goal (between 1–7 exercise sessions/week)

  2.3 Does the app have the ability to review goals, update, and change when necessary?

1

Ability to change weekly exercise goal under the profile tab at any stage

3. Feedback and monitoring

  3.1 Does the app give the user the ability to quickly and easily understand the difference between current action and future goals?

1

Via the graph of weekly exercise days plotted relative to the exercise goal

  3.2 Does the app have the ability to allow the user to easily self-monitor behaviour?

1

Via the graph of weekly exercise days plotted relative to the exercise goal

  3.3 Does the app have the ability to share behaviours with others (including social media or forums) and/or allow for social comparison?

0

  3.4 Does the app have the ability to give the user feedback—either from a person or automatically?

1

Automatic feedback via personalised messages in response to the user inputting data about

- the weekly number of exercise sessions achieved

- the main exercise barrier encountered (if the exercise goal was not achieved)

  3.5 Does the app have the ability to export data from app?

0

  3.6 Does the app provide a material or social reward or incentive?

1

Positive reinforcement/congratulations are provided when the weekly exercise goal is reached or exceeded

  3.7 Does the app provide general encouragement?

1

Visual encouragement provided via

- the graph where weekly exercise days are plotted relative to the weekly exercise goal

- the home tab where progress each week is logged against a visual target (the weekly exercise goal)

Text-based encouragement is provided within all exercise facilitator messages (user receives 2/week during weeks 1–4; 1/week during weeks 5–16; 1/fortnight during weeks 17–24)

4. Actions

  4.1 Does the app have reminders and/or prompts or cues for activity?

1

Weekly reminders provided to log exercise sessions

Regular facilitator messages prompt exercise behaviour (user receives 2/week during weeks 1–4; 1/week during weeks 5–16; 1/fortnight during weeks 17–24)

  4.2 Does the app encourage positive habit formation?

1

Habit formation BCT encouraged in week 8 and week 24 facilitator messages

Habit formation targeted in two exercise barrier response messages^†

Facilitator message: Research shows that people who integrate exercise into their daily lives find it easier to exercise long term. Research also shows people see greater improvements the longer they exercise. The aim is to try make exercise a life habit

‘I forgot to do my exercises’ barrier response message: It can be hard to remember. We suggest making the exercises a habit. Set aside the same time each day to do them. It’s much harder to forget when something is a daily routine

  4.3 Does the app allow or encourage for practice or rehearsal, in addition to daily activities?

1

Ability to log more exercise sessions than the goal each week (up to 7 sessions over 7 days)

  4.4 Does the app provide opportunity to plan for barriers?

1

Barriers addressed if weekly exercise goal not met by:—user being asked to reflect on and select their major barrier to exercise for that week

- based on the barrier selected, a targeted BCT message is then sent with suggestions for overcoming the specific barrier

  4.5 Does the app assist with or suggest restructuring the physical or social environment?

1

Environmental restructuring is adressed in 10 barrier response messages (in response to the user selecting the barrier ‘forgot’) ^†

‘I forgot to do my exercises’ barrier response message: It can be hard to remember to exercise. Try putting your exercise equipment somewhere you will see it every day, this can help trigger your memory to do your exercises

  4.6 Does the app assist with distraction or avoidance?

1

Distraction BCT targeted in five barrier response messages (in response to the user selecting the barrier ‘boring’ or ‘pain limits’)^†

‘I found the exercises boring’ barrier response message: Doing the same exercise again and again can be a drag. Try distracting yourself. What about doing your exercises while watching your favourite TV show?

Total score (out of 21)

17