Absolute Accelerometer-Based Intensity Prescription Compared to Physiological Variables in Pregnant and Nonpregnant Women

Maternal 24-h movement patterns across pregnancy and postpartum: The LIFE-Moms consortium

Objective

Time spent among the 24-h movement behaviors (physical activity [PA], sleep, sedentary behavior [SB]) in the perinatal period is important for maternal and child health. We described changes to 24-h movement behaviors and behavior guideline attainment during pregnancy and postpartum and identified correlates of behavior changes.

Methods

This secondary data analysis included the standard of care group (n = 439) from the U.S.-based Lifestyle Interventions For Expectant Moms (LIFE-Moms) consortium, including persons with overweight and obesity. Wrist-worn accelerometry was used to measure movement behaviors early (9-15 weeks) and late (35-36 weeks) pregnancy, and ∼ 1-year postpartum. Sleep and moderate-to-vigorous PA (MVPA) were compared to adult and pregnancy-specific guidelines, respectively. SB was classified into quartiles. PA and SB context were quantified using questionnaires. Mixed models were used to examine changes in behaviors and guidelines and identify correlates.

Results

Participants were 31.3 ± 3.5 years, 53.5 % were Black or Hispanic, and 45.1 % had overweight. Sleep duration decreased across time, but participants consistently met the guideline (range: 85.0-93.6 %). SB increased during pregnancy and decreased postpartum, while light PA and MVPA followed the inverse pattern. Participants met slightly fewer guidelines late pregnancy (1.2 ± 0.7 guidelines) but more postpartum (1.7 ± 0.8 guidelines) than early pregnancy (1.4 ± 0.8 guidelines). Black or Hispanic race/ethnicity, higher pregravid body mass index, and non-day work-shift (e.g., night-shift) were identified correlates of lower guideline adherence and varying PA and SB context.

Conclusion

Perinatal interventions should consider strategies to prevent SB increase and sustain MVPA to promote guideline adherence.

Accelerometer-Derived Intensity Thresholds Are Equivalent to Standard Ventilatory Thresholds in Incremental Running Exercise

Accelerometer cut-points are commonly used to prescribe the amount of physical activity, but this approach includes no individual performance measures. As running kinetics change with intensity, acceleration measurements may provide more individual information. Therefore, the aim was to determine two intensity thresholds from accelerometer measures. A total of 33 participants performed a maximal incremental running test with spirometric and acceleration (Axivity AX3) measures at the left and right tibia. Ventilatory equivalents (VE/VO2, VE/VCO2) were used to determine a first and second ventilatory threshold (VT1/VT2). A first and second accelerometer threshold (ACT1/ACT2) were determined within the same regions of interest from vector magnitude (|v| = √(ax2 + ay2 + az2). Accelerometer data from the tibia presented a three-phase increase with increasing speed. Speed at VT1/VT2 (7.82 ± 0.39/10.91 ± 0.87 km/h) was slightly but significantly lower compared to the speed at ACT1/ACT2 from the left (7.71 ± 0.35/10.62 ± 0.72 km/h) and right leg (7.79 ± 0.33/10.74 ± 0.77 km/h). Correlation analysis revealed a strong relationship between speed at thresholds determined from spriometric data or accelerations (r = 0.98; p < 0.001). It is therefore possible to determine accelerometer thresholds from tibia placement during a maximal incremental running test comparable to standard ventilatory thresholds.

Physical activity and sedentary time across pregnancy and associations with neonatal weight, adiposity and cord blood parameters: a secondary analysis of the DALI study

BACKGROUND/OBJECTIVES

Obesity during pregnancy is associated with neonatal adiposity, which is a risk factor for childhood obesity. Maternal physical activity (PA) and sedentary behaviours during pregnancy might modify this risk. We therefore studied associations between maternal PA and sedentary time (ST) during pregnancy and neonatal anthropometry and cord blood parameters and investigated whether associations differed by offspring sex.

SUBJECTS/METHODS

Participants of the Vitamin D And Lifestyle Intervention for Gestational Diabetes Mellitus Prevention (DALI) study with a BMI  ≥ 29 kg/m2 were analysed as a cohort. Maternal moderate-to-vigorous PA (MVPA) and ST were measured repeatedly with accelerometers across pregnancy. Associations between mean levels and changes in MVPA and ST and birthweight, neonatal adiposity (fat mass (FM)%) and cord blood parameters, including C-peptide, leptin and lipids, were analysed in 213 mother-child pairs with Bayesian multilevel models. Interactions with offspring sex were considered.

RESULTS

Almost all women decreased MVPA levels and increased ST throughout gestation. Both higher maternal mean MVPA and increasing MVPA were associated with lower offspring FM% in males (-0.520%; 95% CI: -1.011%, -0.031% and -4.649%; -7.876%, -1.432% respectively). In female offspring, mean ST was associated with lower cord blood C-peptide (-0.145 µg/l; -0.279 µg/l, -0.005 µg/l). No associations were found with birthweight or other cord blood parameters.

CONCLUSIONS

Maternal MVPA is associated with neonatal fat mass, but not birthweight, in male offspring. Our findings underline the importance of physical activity throughout pregnancy.

Changes in self-reported and accelerometer-measured physical activity among pregnant TRICARE Beneficiaries

Background

Physical activity is recommended for all pregnant individuals and can prevent excessive gestational weight gain. However, physical activity has not been assessed among military personnel and other TRICARE beneficiaries, who experience unique military lifestyles. The current study assessed physical activity among pregnant TRICARE beneficiaries, both active duty and non-active duty, as measured by accelerometry and self-report data to examine potential predictors of physical activity engagement in the third trimester, and if self-report data was consistent with accelerometry data. We expected having a lower BMI, being active-duty, and having higher baseline physical activity engagement to be associated with higher physical activity at 32-weeks. We also hypothesized that accelerometry data would show lower physical activity levels than the self-reported measure.

Methods

Participants were 430 TRICARE adult beneficiaries (204 Active Duty; 226 non-Active Duty) in San Antonio, TX who were part of a randomized controlled parent study that implemented a stepped-care behavioral intervention. Participants were recruited if they were less than 12-weeks gestation and did not have health conditions precluding dietary or physical activity changes (e.g., uncontrolled cardiovascular conditions) or would contribute to weight changes. Participants completed self-report measures and wore an Actical Activity Monitor accelerometer on their wrist to collect physical activity data at baseline and 32-weeks gestation.

Results

Based on the accelerometer data, 99% of participants were meeting moderate physical activity guidelines recommending 150 min of moderate activity per week at baseline, and 96% were meeting this recommendation at 32-weeks. Based on self-report data, 88% of participants at baseline and 92% at 32-weeks met moderate physical activity recommendations. Linear regression and zero-inflated negative binomial models indicated that baseline physical activity engagement predicted moderate physical activity later in pregnancy above and beyond BMI and military status. Surprisingly, self-reported data, but not accelerometer data, showed that higher baseline activity was associated with decreased vigorous activity at 32-weeks gestation. Additionally, self-report and accelerometry data had small correlations at baseline, but not at 32-weeks.

Conclusions

Future intervention efforts may benefit from intervening with individuals with lower pre-pregnancy activity levels, as those who are active seem to continue this habit.

Trial Registration

The trial is registered on clinicaltrials.gov (NCT 03057808).

Assessment of physical fitness during pregnancy: validity and reliability of fitness tests, and relationship with maternal and neonatal health - a systematic review

Objectives

To systematically review studies evaluating one or more components of physical fitness (PF) in pregnant women, to answer two research questions: (1) What tests have been employed to assess PF in pregnant women? and (2) What is the validity and reliability of these tests and their relationship with maternal and neonatal health?

Design

A systematic review.

Data sources

PubMed and Web of Science.

Eligibility criteria

Original English or Spanish full-text articles in a group of healthy pregnant women which at least one component of PF was assessed (field based or laboratory tests).

Results

A total of 149 articles containing a sum of 191 fitness tests were included. Among the 191 fitness tests, 99 (ie, 52%) assessed cardiorespiratory fitness through 75 different protocols, 28 (15%) assessed muscular fitness through 16 different protocols, 14 (7%) assessed flexibility through 13 different protocols, 45 (24%) assessed balance through 40 different protocols, 2 assessed speed with the same protocol and 3 were multidimensional tests using one protocol. A total of 19 articles with 23 tests (13%) assessed either validity (n=4), reliability (n=6) or the relationship of PF with maternal and neonatal health (n=16).

Conclusion

Physical fitness has been assessed through a wide variety of protocols, mostly lacking validity and reliability data, and no consensus exists on the most suitable fitness tests to be performed during pregnancy.

PROSPERO registration number

CRD42018117554.

Comparison of Outcomes Derived from the ActiGraph GT3X+ and the Axivity AX3 Accelerometer to Objectively Measure 24-Hour Movement Behaviors in Adults: A Cross-Sectional Study

The aim of this cross-sectional study is to investigate convergent validity of outcomes derived from the ActiGraph GT3X and Axivity accelerometer and to investigate feasibility and acceptability of using outcomes derived from these devices to measure 24-h movement behaviors (i.e., sleep, sedentary behavior, and physical activity) in adults during free-living conditions. Twenty-four adults (33.3% male; 39.79 ± 13.09 years old) simultaneously wore a hip-mounted ActiGraph and thigh-mounted Axivity during 48 consecutive hours. The ActiGraph was switched from hip to wrist during the night. To assess convergent validity between the two devices, Paired sample t-tests, linear regressions, Bland-Altman plots and κ statistic were conducted. Feasibility and acceptability of the devices was self-reported on a five-point scale. Daily time spent in 24-h movement behaviors differed between both devices. Except for sleep, the mean differences in daily time spent in the behaviors were clinically relevant and the limits of agreement were wide. For all 24-h movement behaviors, except for sleep and vigorous physical activity, proportional errors were observed. κ statistic showed substantial agreement for total physical activity and outstanding agreement for sedentary behavior and sleep. Adults perceived the Axivity as more practical than the ActiGraph to wear it for more than two days whereas the feasibility to wear it for two days was comparable. Depending on the measure, the observed biases were clinically relevant, proportional to the size of the measure and/or erratically variable. When taking into account the data processing approaches applied in this study, the ActiGraph and the Axivity cannot be used interchangeably to measure 24-h movement behaviors since the bias between both devices is clinically relevant and unpredictable.