The Effectiveness of a Computer-Tailored Web-Based Physical Activity Intervention Using Fitbit Activity Trackers in Older Adults (Active for Life): Randomized Controlled Trial

Background Physical activity is an integral part of healthy aging; yet, most adults aged ≥65 years are not sufficiently active. Preliminary evidence suggests that web-based interventions with computer-tailored advice and Fitbit activity trackers may be well suited for older adults. Objective The aim of this study was to examine the effectiveness of Active for Life, a 12-week web-based physical activity intervention with 6 web-based modules of computer-tailored advice to increase physical activity in older Australians. Methods Participants were recruited both through the web and offline and were randomly assigned to 1 of 3 trial arms: tailoring+Fitbit, tailoring only, or a wait-list control. The computer-tailored advice was based on either participants’ Fitbit data (tailoring+Fitbit participants) or self-reported physical activity (tailoring-only participants). The main outcome was change in wrist-worn accelerometer (ActiGraph GT9X)–measured moderate to vigorous physical activity (MVPA) from baseline to after the intervention (week 12). The secondary outcomes were change in self-reported physical activity measured by means of the Active Australia Survey at the midintervention point (6 weeks), after the intervention (week 12), and at follow-up (week 24). Participants had a face-to-face meeting at baseline for a demonstration of the intervention and at baseline and week 12 to return the accelerometers. Generalized linear mixed model analyses were conducted with a γ distribution and log link to compare MVPA and self-reported physical activity changes over time within each trial arm and between each of the trial arms. Results A total of 243 participants were randomly assigned to tailoring+Fitbit (n=78, 32.1%), tailoring only (n=96, 39.5%), and wait-list control (n=69, 28.4%). Attrition was 28.8% (70/243) at 6 weeks, 31.7% (77/243) at 12 weeks, and 35.4% (86/243) at 24 weeks. No significant overall time by group interaction was observed for MVPA (P=.05). There were no significant within-group changes for MVPA over time in the tailoring+Fitbit group (+3%, 95% CI –24% to 40%) or the tailoring-only group (–4%, 95% CI –24% to 30%); however, a significant decline was seen in the control group (–35%, 95% CI –52% to –11%). The tailoring+Fitbit group participants increased their MVPA 59% (95% CI 6%-138%) more than those in the control group. A significant time by group interaction was observed for self-reported physical activity (P=.02). All groups increased their self-reported physical activity from baseline to week 6, week 12, and week 24, and this increase was greater in the tailoring+Fitbit group than in the control group at 6 weeks (+61%, 95% CI 11%-133%). Conclusions A computer-tailored physical activity intervention with Fitbit integration resulted in improved MVPA outcomes in comparison with a control group in older adults. Trial Registration Australian New Zealand Clinical Trials Registry ACTRN12618000646246; https://anzctr.org.au/Trial/Registration/TrialReview.aspx?ACTRN=12618000646246

The CONSORT-EHEALTH checklist is intended for authors of randomized trials evaluating web-based and Internet-based applications/interventions, including mobile interventions, electronic games (incl multiplayer games), social media, certain telehealth applications, and other interactive and/or networked electronic applications. Some of the items (e.g. all subitems under item 5 -description of the intervention) may also be applicable for other study designs.
The goal of the CONSORT EHEALTH checklist and guideline is to be a) a guide for reporting for authors of RCTs, b) to form a basis for appraisal of an ehealth trial (in terms of validity) CONSORT-EHEALTH items/subitems are MANDATORY reporting items for studies published in the Journal of Medical Internet Research and other journals / scientific societies endorsing the checklist.
As the CONSORT-EHEALTH checklist is still considered in a formative stage, we would ask that you also RATE ON A SCALE OF 1-5 how important/useful you feel each item is FOR THE PURPOSE OF THE CHECKLIST and reporting guideline (optional).
Mandatory reporting items are marked with a red *. In the textboxes, either copy & paste the relevant sections from your manuscript into this form -please include any quotes from your manuscript in QUOTATION MARKS, or answer directly by providing additional information not in the manuscript, or elaborating on why the item was not relevant for this study. yes: all primary outcomes were significantly better in intervention group vs control partly: SOME primary outcomes were significantly better in intervention group vs control no statistically significant difference between control and intervention potentially harmful: control was significantly better than intervention in one or more outcomes inconclusive: more research is needed Other: not submitted yet -in early draft status not submitted yet -in late draft status, just before submission submitted to a journal but not reviewed yet submitted to a journal and after receiving initial reviewer comments submitted to a journal and accepted, but not published yet If this is a JMIR submission, please provide the manuscript tracking number under "other" (The ms tracking number can be found in the submission acknowledgement email, or when you login as author in JMIR. If the paper is already published in JMIR, then the ms tracking number is the four-digit number at the end of the DOI, to be found at the bottom of each published article in JMIR) Identify the mode of delivery. Preferably use "web-based" and/or "mobile" and/or "electronic game" in the title. Avoid ambiguous terms like "online", "virtual", "interactive". Use "Internet-based" only if Intervention includes non-web-based Internet components (e.g. email), use "computer-based" or "electronic" only if offline products are used. Use "virtual" only in the context of "virtual reality" (3-D worlds). Use "online" only in the context of "online support groups". Complement or substitute product names with broader terms for the class of products (such as "mobile" or "smart phone" instead of "iphone"), especially if the application runs on different platforms. Copy and paste relevant sections from manuscript title (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study "web-based"  e  a  t  u  r  e  s  /  f  u  n  c  t  i  o  n  a  l  i  t  i  e  s  /  c  o  m  p  o  n  e  n  t  s  o  f  t  h  e  i  n  t  e  r  v  e  n  t  i  o  n  a  n  d  c  o  m  p  a  r  a  t  o  r  i  n  t  h  e  M  E  T  H  O  D  S  s  e  c  t  i  o  n  o  f  t  h  e  A  B  S  T  R  A  C  T Mention key features/functionalities/components of the intervention and comparator in the abstract. If possible, also mention theories and principles used for designing the site. Copy and paste relevant sections from the manuscript abstract (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study "one of three trial arms: 1) tailoring + Fitbit, 2) tailoring only, or 3) a wait-list control. The tailored advice was based on either participants' Fitbit data (tailoring + Fitbit participants) or self-reported physical activity (tailoring only participants)." Clarify the level of human involvement in the abstract, e.g., use phrases like "fully automated" vs. "therapist/nurse/care provider/physician-assisted" (mention number and expertise of providers involved, if any).  t  o  -f  a  c  e  a  s  s  e  s  s  m  e  n  t  s  i  n  t  h  e  M  E  T  H  O  D  S  s  e  c  t  i  o  n  o  f  t  h  e  A  B  S  T  R  A  C  T Mention how participants were recruited (online vs. offline), e.g., from an open access website or from a clinic or a closed online user group (closed usergroup trial), and clarify if this was a purely web-based trial, or there were face-to-face components (as part of the intervention or for assessment). Clearly say if outcomes were self-assessed through questionnaires (as common in web-based trials Copy and paste relevant sections from the manuscript abstract (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study "A total of 243 participants recruited both online and offline were randomly assigned to one of three trial arms." "Participants had a face-to-face meeting at baseline and week 12 to demonstrate the intervention and collect accelerometers." "wrist-worn accelerometer (Actigraph GT9X) measured moderate to vigorous physical activity (MVPA)" "self-reported physical activity measured via the Active Australia Questionnaire"  I  N  T  R  O  D  U  C  T  I  O  N   2  a  )  I  n  I  N  T  R  O  D  U  C  T  I  O  N  :  S  c  i  e  n  t  i  f  i  c  b  a  c  k  g  r  o  u  n  d  a  n  d  e  x  p  l  a  n  a  t  i  o  n  o  f  r  a  t  i  o  n  a  l  e   D  o  e  s  y  o  u  r  p  a  p  e  r  a  d  d  r  e  s  s  s  u  b  i  t  e  m  1  b  -i  v  ? Copy and paste relevant sections from the manuscript abstract (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study "A total of 243 participants were randomly assigned to 1) tailoring + Fitbit (n=78), 2) tailoring only (n=96), and 3) wait-list control (n=69)." "Attrition was 29% at 6 weeks, 32% at 12 weeks and 35% at 24 weeks." A second paper has been drafted to report usage and adherence and it is therefore not included in the abstract or main body of this main outcomes paper.
Conclusions/Discussions in abstract for negative trials: Discuss the primary outcome -if the trial is negative (primary outcome not changed), and the intervention was not used, discuss whether negative results are attributable to lack of uptake and discuss reasons. Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study "It is hypothesised that the web-based computer tailored physical activity intervention with Fitbit integration will lead to increased objectively measured MVPA and self-reported physical activity over time and decreased objectively measured sedentary behaviour and self-reported sitting time over time compared to the web-based computer tailored physical activity intervention without Fitbit integration and a control group." Open vs. closed, web-based vs. face-to-face assessments: Mention how participants were recruited (online vs. offline), e.g., from an open access website or from a clinic, and clarify if this was a purely webbased trial, or there were face-to-face components (as part of the intervention or for assessment), i.e., to what degree got the study team to know the participant. In online-only trials, clarify if participants were quasi-anonymous and whether having multiple identities was possible or whether technical or logistical measures (e.g., cookies, email confirmation, phone calls) were used to detect/prevent these.
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study "Participants were recruited in Rockhampton (Regional Queensland), Bundaberg (Regional Queensland), and Adelaide (Metropolitan South Australia), Australia via paid Facebook advertising, email lists, flyers and local newsletters. Recruitment was carried out between April 2018 and March 2019 and data collection finished in November 2019." "Participants attended a baseline appointment to return the baseline accelerometer and were randomly allocated to one of the three trial arms (tailoring + Fitbit, tailored advice only and wait list control)." "During the appointment, after randomisation, intervention group participants were shown through the Active for Life intervention website and Fitbit participants were provided with a Fitbit and shown how to sync it to the intervention website. After the 12-week intervention, participants attended another face-to-face follow up appointment to return the week 12 accelerometer." Information given during recruitment. Specify how participants were briefed for recruitment and in the informed consent procedures (e.g., publish the informed consent documentation as appendix, see also item X26), as this information may have an effect on user self-selection, user expectation and may also bias results. Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study "Advertising materials directed prospective participants to the landing page of the intervention website which had more details about study participation and access to the participant information sheet and eligibility survey. Prospective participants were automatically notified of their eligibility upon completion of the survey and eligible participants received a welcome email." Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study "Participants were recruited in Rockhampton (Regional Queensland), Bundaberg (Regional Queensland), and Adelaide (Metropolitan South Australia)" Clearly report if outcomes were (self-)assessed through online questionnaires (as common in web-based trials) or otherwise. subitem not at all important Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study "Participants were asked to complete online research surveys at baseline, week 6, week 12 and week 24 through the intervention website. If participants missed a survey, they were still asked to complete later surveys. Participants were posted an accelerometer to wear on their wrist for 7 consecutive 24-hour days including when sleeping and showering at baseline and week 12." Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study N/A. The intervention was developed specifically for research evaluation purposes.

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Describe the history/development process of the application and previous formative evaluations (e.g., focus groups, usability testing), as these will have an impact on adoption/use rates and help with interpreting results. Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study This was covered in detail in the protocol paper which is referenced in the current manuscript. See extract from the protocol paper: Active for Life was based on the 'My Activity Coach' intervention which is effective in inactive middle-aged adults. The intervention was updated based on findings from focus groups investigating the perceptions and preferences of web-based physical activity interventions in adults 65+ years. This included adding sections on the physical activity guidelines for older adults, strength and balance exercises and exercising with illnesses and injury.19 Existing sections including benefits, barriers, self-efficacy, active lifestyles and action planning were modified to be relevant and engaging to adults 65+ years.

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Revisions and updating. Clearly mention the date and/or version number of the application/intervention (and comparator, if applicable) evaluated, or describe whether the intervention underwent major changes during the evaluation process, or whether the development and/or content was "frozen" during the trial.
Describe dynamic components such as news feeds or changing content which may have an impact on the replicability of the intervention (for unexpected events see item 3b).
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study Version 1 was used and no updates or changes were carried out during the trial. Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study The sessions were written by a PhD in physical activity and included references to guidelines from external institutions. The exercises were written by a physiotherapist.

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Ensure replicability by publishing the source code, and/or providing screenshots/screen-capture video, and/or providing flowcharts of the algorithms used. Replicability (i.e., other researchers should in principle be able to replicate the study) is a hallmark of scientific reporting.
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study Multiple screen shots and an example of the questions used to inform the physical activity advice and the physical activity advice itself are included in the current manuscript and referenced protocol paper. Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study The website requires log in so we are unable to archive.

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Access: Describe how participants accessed the application, in what setting/context, if they had to pay (or were paid) or not, whether they had to be a member of specific group. If known, describe how participants obtained "access to the platform and Internet" [1]. To ensure access for editors/reviewers/readers, consider to provide a "backdoor" login account or demo mode for reviewers/readers to explore the application (also important for archiving purposes, see vi). Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study "Participants were recruited in Rockhampton (Regional Queensland), Bundaberg (Regional Queensland), and Adelaide (Metropolitan South Australia), Australia via paid Facebook advertising, email lists, flyers and local newsletters." "Advertising materials directed prospective participants to the landing page of the intervention website which had more details about study participation and access to the participant information sheet and eligibility survey." "Participants attended a baseline appointment to return the baseline accelerometer and were randomly allocated to one of the three trial arms (tailoring + Fitbit, tailored advice only and wait list control)." "During the appointment, after randomisation, intervention group participants were shown through the Active for Life intervention website and Fitbit participants were provided with a Fitbit and shown how to sync it to the intervention website." Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study "The Active for Life intervention is a 12-week online program with 6 modules of tailored advice delivered bi-weekly." "The advice is based on the theory of planned behaviour [32] and the social cognitive theory [33] and includes evidence-based behaviour change techniques [34,35]." "The physical activity advice is tailored to participants' characteristics and environment, physical activity behaviour and psychosocial correlates of physical activity (e.g., selfefficacy and social support)." More detail including the behavior change techniques used in each session can be found in the protocol paper. Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study "The Active for Life intervention is a 12-week online program with 6 modules of tailored advice delivered bi-weekly. " "The intervention website includes an action planning tool which participants are encouraged to complete at the end of module 2 and 4. The tool guides participants in setting an action plan (the what, where, when and with whom) for being active in the following fortnight. The intervention website also includes an exercise library where participants can access strength and flexibility exercise plans written by a physiotherapist at the beginners and/or intermediate level. Clarify the level of human involvement (care providers or health professionals, also technical assistance) in the e-intervention or as co-intervention (detail number and expertise of professionals involved, if any, as well as "type of assistance offered, the timing and frequency of the support, how it is initiated, and the medium by which the assistance is delivered". It may be necessary to distinguish between the level of human involvement required for the trial, and the level of human involvement required for a routine application outside of a RCT setting (discuss under item 21 -generalizability Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study "During the appointment, after randomisation, intervention group participants were shown through the Active for Life intervention website and Fitbit participants were provided with a Fitbit and shown how to sync it to the intervention website. After the 12-week intervention, participants attended another face-to-face follow up appointment to return the week 12 accelerometer." Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study The protocol paper specifies the following: Participants will be sent up to three reminder emails at 2-day intervals when each module becomes available. Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study "During the appointment, after randomisation, intervention group participants were shown through the Active for Life intervention website and Fitbit participants were provided with a Fitbit and shown how to sync it to the intervention website. After the 12-week intervention, participants attended another face-to-face follow up appointment to return the week 12 accelerometer." Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study "The primary aim of the study is to test the effectiveness of a web-based computer tailored physical activity intervention with Fitbit integration at increasing objectively measured MVPA from pre to post intervention compared to a web-based computer tailored physical activity intervention without Fitbit integration and a control group in adults over 65 years of age. The secondary aims are to compare the web-based computer-tailored intervention with and without Fitbit integration and the control group on objectively measured sedentary behaviour from pre to post intervention and to compare subjectively measured physical activity and sitting time changes at mid intervention, post intervention and follow up." Copy and paste relevant sections from manuscript title (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study "To detect differences between intervention groups and control for accelerometer measured MVPA from baseline to post intervention, 100 participants per group were required. This was to detect an effect size of 0.37 based on the average effect size of web-based physical activity interventions for inactive adults Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study "Randomisation lists were created by the lead investigator (SJA)" "Participants were assigned using the randomisation lists by the research manager (DP) and research assistants (CW, TW) by date of baseline appointment." Specify who was blinded, and who wasn't. Usually, in web-based trials it is not possible to blind the participants [1, 3] (this should be clearly acknowledged), but it may be possible to blind outcome assessors, those doing data analysis or those administering co-interventions (if any). Informed consent procedures (4a-ii) can create biases and certain expectations -discuss e.g., whether participants knew which intervention was the "intervention of interest" and which one was the "comparator". Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study "Due to the nature of the intervention neither researchers nor participants were blinded to group allocation." Participants would have known if they were given the intervention of interest or the comparator as the comparator was a waitlist control group. Imputation techniques to deal with attrition / missing values: Not all participants will use the intervention/comparator as intended and attrition is typically high in ehealth trials. Specify how participants who did not use the application or dropped out from the trial were treated in the statistical analysis (a complete case analysis is strongly discouraged, and simple imputation techniques such as LOCF may also be problematic [4]). Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study The ethics committee approval is reported in the referenced protocol paper. Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study "Participants indicated their informed consent through a check box at the beginning of the baseline survey." Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study " Figure 2 shows the flow of participants through the trial. Just over half (54%) of those screened met the eligibility criteria and 41% of those screened completed their baseline assessment and were randomised (n=243). Attrition was 29% at 6 weeks, 32% at 12 weeks and 35% at 24 weeks." Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study These details can be found in figure 2. Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study "The decision to end participant recruitment was made by the lead (SJA) and senior (CV) investigator due to the trial being close to the sample size goal (n=243), limited remaining funds and slowed interest in the trial." Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study Report multiple "denominators" and provide definitions: Report N's (and effect sizes) "across a range of study participation [and use] thresholds" [1], e.g., N exposed, N consented, N used more than x times, N used more than y weeks, N participants "used" the intervention/comparator at specific pre-defined time points of interest (in absolute and relative numbers per group). Always clearly define "use" of the intervention.  In addition to primary/secondary (clinical) outcomes, the presentation of process outcomes such as metrics of use and intensity of use (dose, exposure) and their operational definitions is critical. This does not only refer to metrics of attrition (13-b) (often a binary variable), but also to more continuous exposure metrics such as "average session length". These must be accompanied by a technical description how a metric like a "session" is defined (e.g., timeout after idle time) [1] (report under item 6a). Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study This is included in a separate manuscript (process evaluation of Active for Life). Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study "The main aim of the study was to determine the effectiveness of a computer-tailored physical activity intervention with Fitbit integration compared to a tailoring only and control group at increasing MVPA pre-to post intervention. The second aim was to determine the effectiveness of a computer-tailored physical activity intervention with Fitbit integration compared to a tailoring only and control group at increasing self-reported physical activity from pre-to mid intervention, post intervention and follow up." "The findings show no MVPA changes in the tailoring + Fitbit group or tailoring only group whilst the control group decreased their MVPA. MVPA increased more in the tailoring + Fitbit group compared to the control group." "All groups reported increasing their self-reported physical activity and this increase was greater in the tailoring + Fitbit group compared to the control group mid-intervention." Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study "Whilst attrition at week 12 was moderate (32%), this is comparable to many other trials examining web-based interventions [50,51,52]. Whilst it is unlikely to have had a large impact, it is possible that the monetary incentive for completing the research surveys increased participation in the intervention itself due to greater engagement in the overall study. The face-to face meetings with researchers at pre-and post-intervention may have also increased engagement in the intervention or helped to remove barriers to participation (e.g., syncing Fitbit to the website). Therefore, a lower engagement or additional barriers to participation may arise if the intervention was run without monetary incentives or face-toface meetings. The lack of accelerometer assessed MVPA data at week 24 for the main outcome measure is a limitation. As such, we do not know if the significant difference between the tailoring + Fitbit group and control group at 12 weeks would remain at 24 weeks. The self-reported physical activity outcomes at 24 weeks suggest that physical activity changes were maintained in all groups but needs to be interpreted with caution due to the large differences in objective and self-reported physical activity at baseline and week 12. Participants who completed the week 12 outcomes had a lower BMI compared to those who dropped out. Therefore, the findings cannot be generalized to older adults with a higher BMI. Another limitation is the lack of a Fitbit only group who receive a Fitbit device to track their physical activity without also receiving any tailored advice. This would help to determine whether the improvements in the tailoring + Fitbit group were due to being tracked by the Fitbit device itself, or the combination of the tailored advice based on the Fitbit data. The Fitbit device had 5 lights which each indicate an additional 2000 steps reached for the day which may have also motivated this group to maintain their activity, independent of the computer-tailored advice. Accelerometer wear time increased between baseline and week 12. Although analyses controlled for wear time, the increase in wear time may have had some effect on the decrease in MVPA and increase in sedentary behavior observed in some groups. Further, the number of participants randomized to each group varied due to small numbers recruited within some randomisation groups (e.g. older males) with block sizes within each randomisation group being 15. The control group had a higher level of MVPA at baseline and therefore had more room to decrease their MVPA. This may have contributed to the between group difference observed between the tailoring + Fitbit and control group on MVPA changes at week 12. Lastly, the conservative a priori sample size calculation (n=300) was not met, however we recruited n=243 participants which is comparable to similar studies [9] and there was enough power to detect MVPA group differences between the tailoring + fitbit and control group." Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study "Participants who completed the week 12 outcomes had a lower BMI compared to those who dropped out. Therefore, the findings cannot be generalized to older adults with a higher BMI Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study "Whilst it is unlikely to have had a large impact, it is possible that the monetary incentive for completing the research surveys increased participation in the intervention itself due to greater engagement in the overall study. The face-to face meetings with researchers at preand post-intervention may have also increased engagement in the intervention or helped to remove barriers to participation (e.g., syncing Fitbit to the website). Therefore, a lower engagement or additional barriers to participation may arise if the intervention was run without monetary incentives or face-to-face meetings." Cite a Multimedia Appendix, other reference, or copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study The protocol paper is referenced throughout the methods section e.g. "More detail of the methods can be found in a protocol paper of the trial [28]."  D  o  e  s  y  o  u  r  p  a  p  e  r  a  d  d  r  e  s  s  C  O  N  S  O  R  T  s  u  b  i  t  e  m  2  5 ? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study "SJA (102609) and SS (101240) are, and CV was (100427) supported by a fellowship from the National Heart Foundation of Australia. SS (1125586) and MJA (1141606) are supported by a fellowship from the National Health and Medical Research Council. The project was partially supported by a project grant from CQUniversity and CV's fellowship from the National Heart Foundation of Australia (100427). These funding agencies had no role in the design of the study and collection, analysis, and interpretation of data or in writing and submitting the manuscript." Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or briefly explain why the item is not applicable/relevant for your study This is addressed in a separate online conflicts of interest form to be published alongside the paper.