The ability to compare published grouplevel estimates of objectively measured moderate-to-vigorous physical activity
(MVPA) across studies continues to increase in difficulty. The objective of this study was to develop conversion equations
and demonstrate their utility to compare estimates of MVPA derived from the wrist and hip. Data from three studies of youth
(N = 232, 9-12yrs, 50% boys) who concurrently wore a hip-worn ActiGraph and a wrist-worn GENEActiv for 7-days.
ActiGraph hip count data were reduced using four established cutpoints: Evenson, Pate, Puyau, and Freedson 3MET. Wrist
accelerations were reduced using the Hildebrand MVPA 200 mg threshold. Conversion equations were developed on a
randomly selected subsample of 132 youth. Equations were cross-validated and absolute error, absolute percent error, and
modified Bland-Altman plots were evaluated for conversion accuracy. Across equations R2adj was 0.51-0.56 with
individual-level absolute error in minutes ranging from 7 (wrist-to-hip Puyau) to 14.5 minutes (wrist-to-hip Freedson
3MET) and absolute percent differences ranging from 13.9%-24.5%. Group-level cross-validation to convert hip-to-wrist MVPA resulted in average absolute percent errors ranging from 3.1%-4.9%.Conversion of wrist-to-hip MVPA resulted
in average absolute percent errors ranging from 3.0%-10.0%. We recommend the use of these equations to compare published
estimates of MVPA between the wear-site cut-point combinations presented.