File Download
Links for fulltext
(May Require Subscription)
- Publisher Website: 10.1186/s12874-019-0668-1
- Scopus: eid_2-s2.0-85061246462
- PMID: 30732582
- WOS: WOS:000458142600001
- Find via
Supplementary
- Citations:
- Appears in Collections:
Article: Concurrent validity of the Fitbit for assessing sedentary behavior and moderate-to-vigorous physical activity
Title | Concurrent validity of the Fitbit for assessing sedentary behavior and moderate-to-vigorous physical activity |
---|---|
Authors | |
Keywords | Accelerometer Physical activity Public health Sedentary behavior Validity |
Issue Date | 2019 |
Publisher | BioMed Central Ltd. The Journal's web site is located at http://www.biomedcentral.com/bmcmedresmethodol/ |
Citation | BMC Medical Research Methodology, 2019, v. 19, article no. 29, p. 1-9 How to Cite? |
Abstract | Background:
Recent advances in sensor technologies have promoted the use of consumer-based accelerometers such as Fitbit Flex in epidemiological and clinical research; however, the validity of the Fitbit Flex in measuring sedentary behavior (SED) and physical activity (PA) has not been fully determined against previously validated research-grade accelerometers such as ActiGraph GT3X+. Therefore, the purpose of this study was to examine the concurrent validity of the Fitbit Flex against ActiGraph GT3X+ in a free-living condition.
Methods:
A total of 65 participants (age: M = 42, SD = 14 years, female: 72%) each wore a Fitbit Flex and GT3X+ for seven consecutive days. After excluding sleep and non-wear time, time spent (min/day) in SED and moderate-to-vigorous PA (MVPA) were estimated using various cut-points for GT3X+ and brand-specific algorithms for Fitbit, respectively. Repeated measures one-way ANOVA and mean absolute percent errors (MAPE) served to examine differences and measurement errors in SED and MVPA estimates between Fitbit Flex and GT3X+, respectively. Pearson and Spearman correlations and Bland-Altman (BA) plots were used to evaluate the association and potential systematic bias between Fitbit Flex and GT3X+. PROC MIXED procedure in SAS was used to examine the equivalence (i.e., the 90% confidence interval with ±10% equivalence zone) between the devices.
Results:
Fitbit Flex produced similar SED and low MAPE (mean difference [MD] = 37 min/day, P = .21, MAPE = 6.8%), but significantly higher MVPA and relatively large MAPE (MD = 59–77 min/day, P < .0001, MAPE = 56.6–74.3%) compared with the estimates from GT3X+ using three different cut-points. The correlations between Fitbit Flex and GT3X+ were consistently higher for SED (r = 0.90, ρ = 0.86, P < .01), but weaker for MVPA (r = 0.65–0.76, ρ = 0.69–0.79, P < .01). BA plots revealed that there is no apparent bias in estimating SED.
Conclusion:
In comparison with the GT3X+ accelerometer, the Fitbit Flex provided comparatively accurate estimates of SED, but the Fitbit Flex overestimated MVPA under free-living conditions. Future investigations using the Fitbit Flex should be aware of present findings. |
Persistent Identifier | http://hdl.handle.net/10722/267460 |
ISSN | 2023 Impact Factor: 3.9 2023 SCImago Journal Rankings: 1.632 |
PubMed Central ID | |
ISI Accession Number ID |
DC Field | Value | Language |
---|---|---|
dc.contributor.author | Redenius, N | - |
dc.contributor.author | Kim, Y | - |
dc.contributor.author | Byun, W | - |
dc.date.accessioned | 2019-02-18T09:02:31Z | - |
dc.date.available | 2019-02-18T09:02:31Z | - |
dc.date.issued | 2019 | - |
dc.identifier.citation | BMC Medical Research Methodology, 2019, v. 19, article no. 29, p. 1-9 | - |
dc.identifier.issn | 1471-2288 | - |
dc.identifier.uri | http://hdl.handle.net/10722/267460 | - |
dc.description.abstract | Background: Recent advances in sensor technologies have promoted the use of consumer-based accelerometers such as Fitbit Flex in epidemiological and clinical research; however, the validity of the Fitbit Flex in measuring sedentary behavior (SED) and physical activity (PA) has not been fully determined against previously validated research-grade accelerometers such as ActiGraph GT3X+. Therefore, the purpose of this study was to examine the concurrent validity of the Fitbit Flex against ActiGraph GT3X+ in a free-living condition. Methods: A total of 65 participants (age: M = 42, SD = 14 years, female: 72%) each wore a Fitbit Flex and GT3X+ for seven consecutive days. After excluding sleep and non-wear time, time spent (min/day) in SED and moderate-to-vigorous PA (MVPA) were estimated using various cut-points for GT3X+ and brand-specific algorithms for Fitbit, respectively. Repeated measures one-way ANOVA and mean absolute percent errors (MAPE) served to examine differences and measurement errors in SED and MVPA estimates between Fitbit Flex and GT3X+, respectively. Pearson and Spearman correlations and Bland-Altman (BA) plots were used to evaluate the association and potential systematic bias between Fitbit Flex and GT3X+. PROC MIXED procedure in SAS was used to examine the equivalence (i.e., the 90% confidence interval with ±10% equivalence zone) between the devices. Results: Fitbit Flex produced similar SED and low MAPE (mean difference [MD] = 37 min/day, P = .21, MAPE = 6.8%), but significantly higher MVPA and relatively large MAPE (MD = 59–77 min/day, P < .0001, MAPE = 56.6–74.3%) compared with the estimates from GT3X+ using three different cut-points. The correlations between Fitbit Flex and GT3X+ were consistently higher for SED (r = 0.90, ρ = 0.86, P < .01), but weaker for MVPA (r = 0.65–0.76, ρ = 0.69–0.79, P < .01). BA plots revealed that there is no apparent bias in estimating SED. Conclusion: In comparison with the GT3X+ accelerometer, the Fitbit Flex provided comparatively accurate estimates of SED, but the Fitbit Flex overestimated MVPA under free-living conditions. Future investigations using the Fitbit Flex should be aware of present findings. | - |
dc.language | eng | - |
dc.publisher | BioMed Central Ltd. The Journal's web site is located at http://www.biomedcentral.com/bmcmedresmethodol/ | - |
dc.relation.ispartof | BMC Medical Research Methodology | - |
dc.rights | BMC Medical Research Methodology. Copyright © BioMed Central Ltd. | - |
dc.rights | This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License. | - |
dc.subject | Accelerometer | - |
dc.subject | Physical activity | - |
dc.subject | Public health | - |
dc.subject | Sedentary behavior | - |
dc.subject | Validity | - |
dc.title | Concurrent validity of the Fitbit for assessing sedentary behavior and moderate-to-vigorous physical activity | - |
dc.type | Article | - |
dc.identifier.email | Kim, Y: youngwon@hku.hk | - |
dc.identifier.authority | Kim, Y=rp02498 | - |
dc.description.nature | published_or_final_version | - |
dc.identifier.doi | 10.1186/s12874-019-0668-1 | - |
dc.identifier.pmid | 30732582 | - |
dc.identifier.pmcid | PMC6367836 | - |
dc.identifier.scopus | eid_2-s2.0-85061246462 | - |
dc.identifier.hkuros | 296974 | - |
dc.identifier.volume | 19 | - |
dc.identifier.spage | article no. 29, p. 1 | - |
dc.identifier.epage | article no. 29, p. 9 | - |
dc.identifier.isi | WOS:000458142600001 | - |
dc.publisher.place | United Kingdom | - |
dc.identifier.issnl | 1471-2288 | - |