Defining Valid Activity Monitor Data: A Multimethod Analysis of Weight-Loss Intervention Participants’ Barriers to Wear and First 100 Days of Physical Activity

Round 1

Reviewer 1 Report

This is a well-written study that describes the use of the Fitbit in predominantly female Hispanic adults with obesity. The use of activity monitors has become mainstream and its acceptability has increased in the general population. The research lays out criteria for step count and heart rate and identifies demographic, socio-economic, and technological barriers to meeting those criteria in this population. The inclusion of both qualitative and quantitative data adds strength to the study.

Minor grammatical errors are seen which may be revised.

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

Dear Authors,

Thank you for providing the manuscript corrections, all my questions and comments were properly addressed.

 

 

Author Response

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Reviewer 3 Report

Thanks for this well written interesting paper. 

Just a few minor issues to please consider:

1. In the Abstract, please write WAM in full as the abbreviation is not known by all. 
2. In text reference for SAS (p.6) and ATLAS (p.8) - I wonder if these can be streamlined as they interrupted my flow of reading.
3. Figure 1 on page 9 is not that clear. I'm not if this is just the download version I could access to review, but if it can be improved please do this.
4. Page 11 line 494, "emotional responses to self-monitoring" should match heading used (line 530) below saying "Negative emotional responses to self-monitoring".

 

Author Response

Please find responses in attachment.

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This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

Comments and suggestions regarding the paper “Defining Valid Activity Monitor Data: A Multimethod Analysis of Weight Loss Intervention Participants’ Barriers to Wear and First 100 Days of Fitbit Activity ”

 

 

This paper investigates the appropriate Fitbit wear threshold for PA in a sample of 616 obese, low-income, Hispanic subjects by taking into consideration the heart rate criteria and the step count criteria. A qualitative analysis is also performed to understand the barriers and the issues the subjects had with the wearable technology.

 

1. In line 150, page 4 it says that the subjects had to wear the activity monitor at all times, except when taking a bath or swimming. Did they have to wear the device during sleep ? Thus, is the data collected over 24 hours ?
2. Is there a way to show on a graph the heart rate data for a few subjects ? Is there a way to visualize the data collected in this study ?
3. In lines 167-169, how is an MVPA minute defined ?
4. What is the purpose of looking into Week 1 and Week 13 analysis ? How it compares to the analysis in first 100 days ?
5. The font in Table 3 should be consistent with the font in the other tables.
6. In line 471, Section 3.7, how were those 16 participants selected for the interview ?

 

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

Overall this article is a significant contribution to the body of knowledge for wearable activity monitoring devices. The article is well-written and very informative. 

There is one major concern in statistical methodology. On Lines 247 - 250, the activity measures were "scaled up to approximately 7 days". This is not a valid statistical or scientific method: this is the equivalent of creating data for participants. It is not reasonable to assume that participants who exercised extensively on 2 out of 4 valid wear days also exercised extensively on even one additional day that week.  Some people only exercise strenuously on the weekends or on a set schedule that may only be 2 days total each week. In other words, you may have captured all the MVPA the person performed that week. The use of an average daily measure (across the valid days) is an acceptable way to compare participants without imputing exercise to someone.

The remaining corrections are minor according to line references. See attached file.

 

Comments for author File: Comments.pdf

Author Response

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Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

The authors did a great job addressing both the major concern and the minor edits. Thank you for clarifying the design of the study to show that it was valid and for adding additional analyses to verify some of the results. I hope the authors found the comments and suggestions beneficial. 

I recommend the article for publication.