JMIR Publications

ABSTRACT

Background:

Mobile health applications (mHealth apps) have high potential to address the widespread deficit in physical activity (PA) behaviour; however, they have demonstrated greater impact on short term PA compared to long term. The multi-process action control (M-PAC) framework promotes sustained PA behaviour by combining reflective (e.g., attitudes) and regulatory (e.g., behavioural regulation, emotional regulation) constructs with reflexive (e.g., PA habits, PA identity) constructs. Usability testing during the initial prototyping phases of an mHealth app is important to assess end users’ overall interest in the app, the integrity of the app’s intrinsic properties, and suggestions for improvement prior to feasibility and efficacy testing.

Objective:

To gather usability feedback from end users on the first and second M-PAC app prototypes.

Methods:

We first conducted a workshop focus group study with a convenience sample of adult participants to determine the first impressions of the M-PAC app interface and first three lessons. The findings informed several modifications to the M-PAC app (e.g., defined acronyms, added cards with reduced content) and the Pathverse app platform (e.g., optimized image loading, created a link placeholder image, added a forgot password feature). We subsequently conducted a pilot usability study with adults who were not meeting 150-min/week of moderate-to-vigorous intensity PA (MVPA). They used the M-PAC app and first three lessons for two weeks and then participated in semi-structured interviews and completed the Mobile App Usability Questionnaire (MAUQ) to provide usability and acceptability feedback. The focus groups and interviews were recorded, transcribed, and analysed with content analysis informed by Nielsen’s usability heuristics. The MAUQ scores were analysed descriptively.

Results:

The workshop focus group study involved 15 participants (mean age = 30.40 (±9.49)). The overall layout and content were well received. The language was deemed appropriate, however some terms (e.g. self-efficacy) and acronyms (e.g., FITT) needed definitions. Participants provided several recommendations for the visual design (e.g., more cards with less text), they had challenges in accessing and using the Help module, couldn’t view all images and were unclear on how to create or reset the password. The usability pilot study involved 14 participants (mean age = 41.38 (±12.92); mean MVPA min/week = 66.07 (±57.92)). They liked the overall app layout, content, and language and provided some suggestions, such as more enticing titles, additional and variable forms of content (e.g., visual aids and videos), and diverse images. The app was easy to navigate however, some errors were identified, such as PA monitoring connection problems, broken links, and difficulties entering and modifying data. The mean MAUQ total and subscale scores were the following: total = 5.06 (±1.20), Usefulness = 4.17 (±1.31), Ease of Use = 5.36(±1.27), and Interface and Satisfaction = 5.52(±1.42).

Conclusions:

Overall, the M-PAC app was deemed usable and acceptable. The findings will inform the development of the minimum viable product which will undergo subsequent feasibility testing.