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Comparison of physical activity measures using mobile phone-based CalFit and Actigraph.

Donaire-Gonzalez D, de Nazelle A, Seto E, Mendez M, Nieuwenhuijsen MJ, Jerrett M - J. Med. Internet Res. (2013)

Bottom Line: The CalFit system had lower usability than the Actigraph GT3X because the application lacked a means to turn itself on each time the smartphone was powered on.The CalFit system may provide valid estimates to quantify and classify physical activity.CalFit may prove to be more cost-effective and easily deployed for large-scale population health studies than other specialized instruments because cell phones are already carried by many people.

View Article: PubMed Central - HTML - PubMed

Affiliation: Center for Research in Environmental Epidemiology (CREAL), Barcelona, Catalonia, Spain.

ABSTRACT

Background: Epidemiological studies on physical activity often lack inexpensive, objective, valid, and reproducible tools for measuring physical activity levels of participants. Novel sensing technologies built into smartphones offer the potential to fill this gap.

Objective: We sought to validate estimates of physical activity and determine the usability for large population-based studies of the smartphone-based CalFit software.

Methods: A sample of 36 participants from Barcelona, Spain, wore a smartphone with CalFit software and an Actigraph GT3X accelerometer for 5 days. The ease of use (usability) and physical activity measures from both devices were compared, including vertical axis counts (VT) and duration and energy expenditure predictions for light, moderate, and vigorous intensity from Freedson's algorithm. Statistical analyses included (1) Kruskal-Wallis rank sum test for usability measures, (2) Spearman correlation and linear regression for VT counts, (3) concordance correlation coefficient (CCC), and (4) Bland-Altman plots for duration and energy expenditure measures.

Results: Approximately 64% (23/36) of participants were women. Mean age was 31 years (SD 8) and mean body mass index was 22 kg/m(2) (SD 2). In total, 25/36 (69%) participants recorded at least 3 days with at least 10 recorded hours of physical activity using CalFit. The linear association and correlations for VT counts were high (adjusted R(2)=0.85; correlation coefficient .932, 95% CI 0.931-0.933). CCCs showed high agreement for duration and energy expenditure measures (from 0.83 to 0.91).

Conclusions: The CalFit system had lower usability than the Actigraph GT3X because the application lacked a means to turn itself on each time the smartphone was powered on. The CalFit system may provide valid estimates to quantify and classify physical activity. CalFit may prove to be more cost-effective and easily deployed for large-scale population health studies than other specialized instruments because cell phones are already carried by many people.

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Comparison of average intensity recorded by CalFit and Actigraph GT3X within light, moderate, and vigorous physical activity identified by Actigraph.
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figure4: Comparison of average intensity recorded by CalFit and Actigraph GT3X within light, moderate, and vigorous physical activity identified by Actigraph.

Mentions: The comparison of measures of light, moderate, and vigorous physical activity showed that less than 30% of the variability was attributable to the method of measurement (Figure 3). In contrast to light and moderate physical activity, the CalFit measures of vigorous physical activity showed a tendency to underestimate the duration in vigorous physical activity as activity levels increased (P=.01) compared to the Actigraph GT3X measure (Figure 3, part C). Figure 4 shows there was a significant underestimation in the intensity recorded by CalFit when participants performed vigorous activity according to Actigraph GT3X (CalFit: mean 5.9, SD 1.0; Actigraph: mean 7.1, SD 1.1; P<.001).


Comparison of physical activity measures using mobile phone-based CalFit and Actigraph.

Donaire-Gonzalez D, de Nazelle A, Seto E, Mendez M, Nieuwenhuijsen MJ, Jerrett M - J. Med. Internet Res. (2013)

Comparison of average intensity recorded by CalFit and Actigraph GT3X within light, moderate, and vigorous physical activity identified by Actigraph.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC3713904&req=5

figure4: Comparison of average intensity recorded by CalFit and Actigraph GT3X within light, moderate, and vigorous physical activity identified by Actigraph.
Mentions: The comparison of measures of light, moderate, and vigorous physical activity showed that less than 30% of the variability was attributable to the method of measurement (Figure 3). In contrast to light and moderate physical activity, the CalFit measures of vigorous physical activity showed a tendency to underestimate the duration in vigorous physical activity as activity levels increased (P=.01) compared to the Actigraph GT3X measure (Figure 3, part C). Figure 4 shows there was a significant underestimation in the intensity recorded by CalFit when participants performed vigorous activity according to Actigraph GT3X (CalFit: mean 5.9, SD 1.0; Actigraph: mean 7.1, SD 1.1; P<.001).

Bottom Line: The CalFit system had lower usability than the Actigraph GT3X because the application lacked a means to turn itself on each time the smartphone was powered on.The CalFit system may provide valid estimates to quantify and classify physical activity.CalFit may prove to be more cost-effective and easily deployed for large-scale population health studies than other specialized instruments because cell phones are already carried by many people.

View Article: PubMed Central - HTML - PubMed

Affiliation: Center for Research in Environmental Epidemiology (CREAL), Barcelona, Catalonia, Spain.

ABSTRACT

Background: Epidemiological studies on physical activity often lack inexpensive, objective, valid, and reproducible tools for measuring physical activity levels of participants. Novel sensing technologies built into smartphones offer the potential to fill this gap.

Objective: We sought to validate estimates of physical activity and determine the usability for large population-based studies of the smartphone-based CalFit software.

Methods: A sample of 36 participants from Barcelona, Spain, wore a smartphone with CalFit software and an Actigraph GT3X accelerometer for 5 days. The ease of use (usability) and physical activity measures from both devices were compared, including vertical axis counts (VT) and duration and energy expenditure predictions for light, moderate, and vigorous intensity from Freedson's algorithm. Statistical analyses included (1) Kruskal-Wallis rank sum test for usability measures, (2) Spearman correlation and linear regression for VT counts, (3) concordance correlation coefficient (CCC), and (4) Bland-Altman plots for duration and energy expenditure measures.

Results: Approximately 64% (23/36) of participants were women. Mean age was 31 years (SD 8) and mean body mass index was 22 kg/m(2) (SD 2). In total, 25/36 (69%) participants recorded at least 3 days with at least 10 recorded hours of physical activity using CalFit. The linear association and correlations for VT counts were high (adjusted R(2)=0.85; correlation coefficient .932, 95% CI 0.931-0.933). CCCs showed high agreement for duration and energy expenditure measures (from 0.83 to 0.91).

Conclusions: The CalFit system had lower usability than the Actigraph GT3X because the application lacked a means to turn itself on each time the smartphone was powered on. The CalFit system may provide valid estimates to quantify and classify physical activity. CalFit may prove to be more cost-effective and easily deployed for large-scale population health studies than other specialized instruments because cell phones are already carried by many people.

Show MeSH
Related in: MedlinePlus