Table 1
Sample Characteristics.
| Characteristic | Mean | (SD) | Min | Max |
|---|---|---|---|---|
| Age (years) | 14.62 | (0.60) | 13.58 | 16.03 |
| MVPA (average minutes/day)a | 21.69 | (13.71) | 2.43 | 50.86 |
| Steps per day | 7758.87 | (1763.69) | 5194 | 11899 |
| Miles per day | 3.66 | (1.98) | 1.89 | 11.84 |
| Grade | n | (%) | ||
| Eighth | 22 | (66.67) | ||
| Ninth | 11 | (33.33) | ||
| Hispanic ethnicity | ||||
| Yes | 15 | (45.45) | ||
| No | 18 | (54.55) | ||
| Race | ||||
| Asian | 1 | (3.03) | ||
| Black | 8 | (24.24) | ||
| Indian | 2 | (6.06) | ||
| White | 10 | (30.30) | ||
| Mixed | 2 | (6.06) | ||
| Other | 1 | (3.03) | ||
| Not reported | 9 | (27.27) | ||
| Free or reduced-price lunchb | ||||
| Yes | 19 | (57.58) | ||
| No | 10 | (30.30) | ||
| Not reported | 4 | (12.12) | ||
[i] Note: N = 33. MVPA = moderate-to-vigorous physical activity; Min = minimum; Max = maximum; SD = standard deviation. Percentages may not add to 100 due to rounding error.
a MVPA (n = 24) not reported for 9 participants due to missing data for active minutes.
b Free/reduced-price lunch program used as an indicator of socioeconomic status.
Table 2
Acceptability and Usability Results from the Fitbit Survey.
| Evaluation Component | Fitbit Activity Tracker Questions | Mean | SD |
|---|---|---|---|
| Acceptability | I liked using the Fitbit. | 2.94 | .25 |
| Acceptability | The Fitbit helped me think about my physical activity. | 2.56 | .50 |
| Acceptability | I would recommend a Fitbit to other girls my age. | 2.75 | .44 |
| Usability | The Fitbit was easy to use. | 2.81 | .40 |
| Usability | If I had a Fitbit I would use it on most days. | 2.94 | .25 |
| Fitbit App Questions | Yes (%) | No (%) | |
| Usability | Did you use the Fitbit App? | 28 (87.5) | 4 (12.5) |
| Acceptability | If you used the Fitbit App, did you like it? | 27 (96.4) | 1 (3.6) |
[i] Note: SD = standard deviation; responses based on n = 32. Likert scale of 0) not at all true to 3) very true used for Fitbit Activity Tracker Questions.
Table 3
Qualitative Analysis to Support Acceptability of the Fitbit Activity Tracker and Fitbit App.
| Category and Themes | Sample Excerpts from the Focus Groups |
|---|---|
| Acceptability Themes | |
| Awareness (n = 8) | “I liked the app because it would tell you like exactly how many steps you had” |
| “I like that you could always see like how many steps you got because it made me more aware and encouraged me to be more active” | |
| “So what I’ve noticed when I’ve had the Fitbit was that during the week I wasn’t as active cuz I was always indoors but then on the weekends I would like reach my goal more or go over the goal” | |
| “I liked that it gave off reminders uh for you to get up and moving because I realized after like the sixth or seventh buzz I had to get up from laying down” | |
| Goal-setting (n = 11) | “During the whole week it kind of made me want to reach that goal. I made the 10,000 step goal twice I think” |
| “Be more active so you can reach that goal” | |
| “I wanted to get to the green light so I would walk a lot” | |
| “I liked how it danced when you got your goal because I saw like a lot of people were excited when they got their goal…so yeah it helps” | |
| “It’s also just kind of fun to just tap on it and see how many you know dots there are and how close you are to your goal” | |
| Motivation (n = 14) | “So I think that’s kind of motivation I guess to like be more active” |
| “There are alarms and that helped a lot for me. It will alarm me if I reached halfway to my score and maybe boost me to do more and stuff like that” | |
| “So I would say technology is like…we’re all so motivated so like we’re surrounded by technology like every day our phones included” | |
| “I would say it was kind of like a motivator to me… if I was like laying on the couch like I’d be like man I have to get some steps in. And my sister she likes to do Just Dance on the TV so I’d just go in and hop in with her and do a couple steps” | |
| “I feel like a lot of us were really inspired to do more steps but as it went on I feel like they’d just go in there and do what they normally would do” | |
[i] Note: n = number of focus group excerpts from subjects for each theme.
Table 4
Qualitative Analysis to Support Usability of the Fitbit Activity Tracker and Fitbit App.
| Category and Themes | Sample Excerpts from the Focus Groups |
|---|---|
| Usability Themes | |
| Functionality (n = 5) | “I like the uh…when you got a call and how it would vibrate on your wrist because I was at one of my friend’s birthday parties and my dad called me and all of a sudden my wrist started like vibrating intensely and I started freaking out” |
| “I’d just randomly get like the message notifications where it was the two dots and the purple and I was like, “I don’t have a message. Why are you vibrating?” I was getting confused by that” | |
| “I really liked the fact how on the app you can find and cheer your friends if you aren’t friends with them on that” | |
| “I just like how it tracks…how many steps you’re taking per hour. So that’s pretty helpful” | |
| Visibility (n = 8) | “I like how it showed me like my progression…throughout the day” |
| “So the four dots, they were confusing because I thought you said 25 so I thought 2,500 but then it would get there at like 1,000 so I was starting to get confused. So the dots for me didn’t make sense” | |
| “I like when it blinks all different types of colors once you reach 10,000 steps” | |
| “I liked how after doing a sport it’ll (App) show you that you did a sport instead of just not” | |
| Wearability (n = 8) | “When putting it on and taking it off, it’s like extremely difficult. But I also see why it’s difficult, so you keep it on” |
| “I really liked how comfortable the band was” | |
| “One thing I didn’t like about the Fitbit was when I sleeping like it kind of bothered me, but that was only like only a couple times but it wasn’t no biggie because I knew I could take it off” | |
| “I don’t like things on my wrist. I’ve never liked things on my wrist, so having that on all day like I’d go home and have the urge to take it off, but I have to keep it on” | |
[i] Note: n = number of focus group excerpts from subjects for each theme.