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Convergent Validity of Pedometer and Accelerometer Estimates of Moderate-to-Vigorous Physical Activity of Youth

2011; Human Kinetics; Volume: 8; Issue: s2 Linguagem: Inglês

10.1123/jpah.8.s2.s295

1543-5474

Michael W. Beets, Charles Morgan, Jorge A. Banda, Daniel B. Bornstein, Won Byun, Jonathan A. Mitchell, Lance Munselle, Laura Rooney, Aaron Beighle, Heather Erwin,

Children's Physical and Motor Development

Pedometer step-frequency thresholds (120 steps·min-1, SPM) corresponding to moderate-to-vigorous intensity physical activity (MVPA) have been proposed for youth. Pedometers now have internal mechanisms to record time spent at or above a user-specified SPM. If pedometers provide comparable MVPA (P-MVPA) estimates to those from accelerometry, this would have broad application for research and the general public. The purpose of this study was to examine the convergent validity of P-MVPA to accelerometer-MVPA for youth.Youth (N = 149, average 8.6 years, range 5 to 14 years, 60 girls) wore an accelerometer (5-sec epochs) and a pedometer for an average of 5.7 ± 0.8 hours·day-1. The following accelerometer cutpoints were used to compare P-MVPA: Treuth (TR), Mattocks (MT), Evenson (EV), Puyau (PU), and Freedson (FR) child equation. Comparisons between MVPA estimates were performed using Bland-Altman plots and paired t tests.Overall, P-MVPA was 24.6 min ± 16.7 vs. TR 25.2 min ± 16.2, MT 18.8 min ± 13.3, EV 36.9 min ± 21.0, PU 22.7 min ± 15.1, and FR 50.4 min ± 25.5. Age-specific comparisons indicated for 10 to 14 year-olds MT, PU, and TR were not significantly different from P-MVPA; for the younger children (5-8 year- olds) P-MVPA consistently underestimated MVPA.Pedometer-determined MVPA provided comparable estimates of MVPA for older children (10-14 year-olds). Additional work is required to establish age appropriate SPM thresholds for younger children.