Validation of Accelerometry Cut-off Points to Categorize Physical Activity Intensity Along the Pregnancy

BackgroundSeveral studies have created and validated accelerometry cut-off points to categorize intensities of physical activity (PA); however, there is not specific cut-off points in pregnant women. Pregnancy promotes specific physiological and biomechanical changes that can modify quantitively the relationship between movement and energy expenditure. The aim of this study was to develop and validate specific accelerometry cut-off points for light and moderate-vigorous PA (LPA and MVPA respectively), at each trimester of pregnancy. Methodology31 healthy pregnant women completed the same cardiopulmonary submaximal exercise test, at each trimester of their pregnancies. Indirect calorimetry variables and accelerometry data were registered from no-dominant wrist and right hip placements at each measurement. Internal load variables (%VO2max, %VO2R, %HR max, %HRR and METs) were used as reference for validation and ROC analyses was performed to estimate cut-off points at each trimester and location in counts/min, MIMs and EMNO units. ResultsCut-off points obtained from the ROC analysis showed a high performance with areas under curves (AUCs) above 0.90. Cut-off points tended to be higher in no-dominant wrist than in right hip location. The cut-off for MVPA on the right hip decreased after the second trimester in ENMO and MIMS units. Only slight differences between trimesters were found in cut-off points for wrist location. ConclusionAccelerometer intensity cut-off points in counts, MIMS and ENMO were validated in each trimester with internal load variables for no-dominant wrist and right hip placements.