Accuracy of physical activity monitors in pregnant women

Women's perceptions of maternal and fetal health benefits of physical activity during pregnancy and what factors impact them-A cross-sectional study

BACKGROUND

Despite the WHO and ACOG's recommendations for at least 150 min of weekly moderate-intensity physical activity during pregnancy, adherence remains low, partly due to concerns about safety and efficacy of specific exercise modalities.

OBJECTIVE

To evaluate pregnant women's outcome expectancy for maternal and fetal health regarding specific physical activity modalities and the influence of healthcare provider discussions on these perceptions.

METHODS

A cross-sectional survey, distributed through Qualtrics (a platform to help design and distribute surveys) and word of mouth of 507 pregnant women assessed perceptions of moderate, vigorous, and resistance activities. Provider discussions and past adverse pregnancy experiences were likewise examined for their influence on outcome expectancy.

RESULTS

Walking and yoga were perceived as the most beneficial modalities for both maternal and fetal health, with the outcome expectancies being 9.5 ± 2.1 and 8.8 ± 2.9 for maternal health and 9.0 ± 2.5 and 8.2 ± 3.0 for fetal health. Higher intensity and resistance activities were viewed less favorably, especially CrossFit® resistance training with outcome expectancies being 5.2 ± 3.4 for maternal health and 4.8 ± 3.3 for fetal health. All physical activities were viewed as more beneficial for maternal health than fetal health. Discussions with healthcare providers occurred in over 70 % of cases but did not generally relate to these perceptions. Past adverse pregnancy experiences were not related to statistically significant changes in outcome expectancy. Previously being prescribed bed rest had some weak associations with greater maternal and fetal outcome expectancy for a few physical activity modalities.

CONCLUSIONS

Pregnant women's perceptions of health benefits clearly differ based on modality of activity and dependent on whether maternal or fetal health. Targeted communication strategies from healthcare providers and public health efforts are needed to improve perceptions of physical activity during pregnancy, especially for vigorous and resistance activities.

Estimating energy requirements from Dietary Reference Intakes for pregnant people with obesity using wearables

OBJECTIVE

Estimating physical activity levels (PAL) is difficult outside of the laboratory, and patient-reported PAL are often overestimated. Herein, we determine the importance of selecting the correct PAL when computing estimated energy requirements (EER) to determine gestational weight gain (GWG). Then, we examine whether data from a wearable can be used to select PAL and predict EER.

METHODS

PAL were measured at early and late pregnancy among 53 pregnant female individuals (BMI > 30 kg/m2) in the laboratory and from wearables. To simulate overreporting physical activity, PAL in early pregnancy were used to compute EER in late pregnancy and assess the effect on GWG.

RESULTS

PAL decreased from early to late pregnancy (p = 0.01). When simulating the effect of overestimating physical activity on EER in late pregnancy, excess GWG occured in all individuals (p < 0.001) with decreased PAL during pregnancy. Average daily step counts and activity minutes in early and late pregnancy overlapped across PAL and are not recommended for use.

CONCLUSIONS

Step count and activity minute data from wearables cannot be used to determine PAL in pregnant individuals with obesity. To minimize excess GWG risks, our outcomes suggest assuming "inactive" physical activity when estimating EER for pregnant people with obesity.

Perception and reality: The mismatch between absolute and relative physical activity intensity during pregnancy and postpartum in United States women

OBJECTIVE

To explore whether a mismatch between absolute physical activity intensity (PAI) and relative self-reported PAI exists during pregnancy and postpartum.

METHODS

Women from the PIN3/Postpartum study completed physical activity questionnaires during pregnancy (n = 770; Trimester 2: T2, Trimester 3: T3) and postpartum (n = 181; 3 months: PP3, 12 months PP12) (2001-2005). Activities women engaged in were assigned Metabolic Equivalent (MET) values for absolute intensity; women self-reported perceived exertion (using the Borg scale) for each activity to provide relative intensity. Hierarchical regression models were used to determine whether a mismatch between absolute and relative PAI (for moderate or vigorous physical activity (MPA; VPA)) differed during pregnancy and postpartum. Models were adjusted for socio-demographic factors.

RESULTS

Women commonly overestimated the amount of MPA and VPA they engaged in [T2 MPA mean 60.5 min/week (49.1, 72.0), VPA 3.7 (-1.4, 8.8); T3: MPA 47.7 (38.9, 56.4), 2.9 (-1.7, 7.4); PP3: MPA 69.5 (43.9, 95.1), VPA 15.8 (1.8, 29.7); PP12: MPA 42.20 (26.8, 57.6), VPA 2.75 (-7.8, 12.9)]. Women overestimated both MPA and VPA to a lesser extent at T3 compared to T2 (MPA: β for difference:-12.6 [95%CI: -26.0, -0.9]; VPA: -0.9 [-6.4, 4.6]). Women continued to overestimate their MPA at PP3 and PP12.

CONCLUSIONS

Compared to absolute PAI, perceived PAI was greater for MPA compared to VPA and differences persisted from pregnancy through postpartum. Future research should focus on how perceptions relate to women's actual physiological capacity and whether this mismatch influences the amount of physical activity women engage in during the transition to motherhood.

Occupational physical activity as a determinant of daytime activity patterns and pregnancy and infant health

Though physical activity (PA) is recommended during pregnancy, it remains unclear how occupational physical activity (OPA) and sedentary behavior (SB) contribute to activity patterns and health during pregnancy. The purpose of this secondary analysis was to determine if OPA pattern is a determinant of all-day PA and evaluate associations with pregnancy/infant health outcomes. Data was from two prospective cohorts with study visits each trimester: MoM Health (Pittsburgh, PA; n = 120) and PRAMS (Iowa City, Iowa; n = 20). Using employment status/job hours (self-reported in demographic questionnaires) and OPA from the Pregnancy Physical Activity Questionnaire, latent class analysis identified three groups: sitting (n = 61), part-time mixed (n = 9), and active (n = 29). A fourth group included non-working participants (n = 32). Device-based PA (ActiGraph GT3X), SB (activPAL3 micro), and blood pressure were measured each trimester. Glucose screening test, gestational age, gestational weight gain, adverse pregnancy outcomes (APOs: gestational hypertension, preeclampsia, eclampsia, gestational diabetes, intrauterine growth restriction, and preterm birth), and infant outcomes (length, weight, and sex) were abstracted from medical records. Associations between groups with APOs and pregnancy/infant health were calculated using linear/logistic regression with adjustment for age, pre-pregnancy BMI, education, and race. Self-reported participant characteristics were similar across groups, except education which was higher in the sitting versus other groups. All-day device-based PA differed across groups; for example, the sitting group had the highest SB across trimester (all p<0.01) while the active group had the highest steps per day across trimesters (all p<0.01). Pregnancy/infant health did not differ between groups (all p>0.09). Compared to the non-working group, the risk of any APO was non-significantly higher in the sitting (OR = 2.27, 95%CI = 0.63-8.18) and active groups (OR = 2.40, 95%CI = 0.66-9.75), though not the part-time mixed (OR = 0.86, 95%CI = 0.08-9.1). OPA pattern is a determinant of all-day PA during pregnancy. Future studies with larger samples should examine associations between pregnancy OPA patterns and pregnancy/infant health.

Patterns in Prenatal Physical Activity and Sedentary Behavior: Associations With Blood Pressure and Placental Features in the MoMHealth Cohort

BACKGROUND

Moderate to vigorous physical activity (MVPA) and sedentary behavior (SED) are associated with blood pressure (BP) and adverse pregnancy outcomes. The authors investigated associations of prenatal MVPA and SED patterns with BP and with placental malperfusion features.

METHODS

Women enrolled in this prospective cohort study in the first trimester. MVPA, SED, and BP were measured objectively each trimester. MVPA and SED trajectories were constructed. Placental examinations were conducted in a subset. Associations of trajectories with BPs were assessed with linear regression adjusted for age, race, education, prepregnancy body mass index, and gestational age. Associations with placental malperfusion lesions and weight were adjusted for key covariates.

RESULTS

One hundred eleven participants were included; placental exams were available in 50. Participants with high (vs low) SED were younger and more likely to have adverse pregnancy outcomes. High SED (vs low) was associated with higher first trimester systolic (β = 5.3; 95% confidence interval, 0.0 to 10.6) and diastolic (β = 5.0; 95% confidence interval, 1.4 to 8.6) and higher second trimester diastolic (β = 4.9; 95% confidence interval, 1.6 to 8.2) BP. Medium and high MVPA groups were associated with lower postpartum diastolic BP. Trajectories were not associated with placental malperfusion.

CONCLUSIONS

MVPA and SED patterns were differentially associated with prenatal and postpartum BP. Encouraging favorable levels of both might help women achieve lower BP during and after pregnancy.

Concurrent Agreement Between ActiGraph and activPAL for Measuring Physical Activity in Pregnant Women and Office Workers

INTRODUCTION

Current best practice for objective measurement of sedentary behavior and moderate-to-vigorous intensity physical activity (MVPA) requires two separate devices. This study assessed concurrent agreement between the ActiGraph GT3X and the activPAL3 micro for measuring MVPA to determine if activPAL can accurately measure MVPA in addition to its known capacity to measure sedentary behavior.

METHODS

Forty participants from two studies, including pregnant women (n = 20) and desk workers (n = 20), provided objective measurement of MVPA from waist-worn ActiGraph GT3X and thigh-worn activPAL micro3. MVPA from the GT3X was compared with MVPA from the activPAL using metabolic equivalents of task (MET)- and step-based data across three epochs. Intraclass correlation coefficient and Bland-Altman analyses, overall and by study sample, compared MVPA minutes per day across methods.

RESULTS

Mean estimates of activPAL MVPA ranged from 22.7 to 35.2 (MET based) and 19.7 to 25.8 (step based) minutes per day, compared with 31.4 min/day (GT3X). MET-based MVPA had high agreement with GT3X, intraclass correlation coefficient ranging from .831 to .875. Bland-Altman analyses revealed minimal bias between 15- and 30-s MET-based MVPA and GT3X MVPA (-3.77 to 8.63 min/day, p > .10) but with wide limits of agreement (greater than ±27 min). Step-based MVPA had moderate to high agreement (intraclass correlation coefficient: .681-.810), but consistently underestimated GT3X MVPA (bias: 5.62-11.74 min/day, p < .02). For all methods, activPAL appears to better estimate GT3X at lower quantities of MVPA. Results were similar when repeated separately by pregnant women and desk workers.

CONCLUSION

activPAL can measure MVPA in addition to sedentary behavior, providing an option for concurrent, single device monitoring. MET-based MVPA using 30-s activPAL epochs provided the best estimate of GT3X MVPA in pregnant women and desk workers.

Associations of objectively measured physical activity and sedentary time with pregnancy-specific health-related quality of life

PURPOSE

To examine associations of objectively measured moderate-to-vigorous-intensity physical activity (MVPA) and sedentary behavior (SED) with pregnancy-specific health-related quality of life (QoL) across pregnancy trimesters.

MATERIALS AND METHODS

Women (N=131, mean age 30.9 years ± 4.9) were recruited from two large health care systems in the United States. MVPA and SED were estimated using a waist-worn ActiGraph GT3X and thigh-worn activPAL3 micro, respectively, for seven days in each trimester of pregnancy. Questionnaires were administered in each trimester to assess pregnancy-specific health-related QoL using the Nausea and Vomiting of Pregnancy Specific health Related Quality of Life (NVPQoL) questionnaire. Mixed effects linear regression examined associations of MVPA and SED with the NVPQoL total score and domain-specific scores (physical symptoms, fatigue, emotions, and limitations) across trimesters.

RESULTS

The NVPQoL total score and domain-specific scores significantly varied across trimesters, with highest scores (indicating worse QoL) observed in the first trimester and lowest scores (indicating better QoL) in the second trimester. A 1-standard deviation (SD) increment in MVPA (16.0 min/day or 1.8%) was associated with better QoL as indicated by the lower NVPQoL total score (β=-4.06, p=0.024) and limitations score (β = -2.80, p<0.001). A 1-SD increment in SED (1.5 hr/day or 10.0%) was associated with worse QoL as indicated by the higher fatigue score (β = 0.82, p=0.041).

CONCLUSIONS

Pregnancy-specific health-related QoL varies across trimesters. Both lower SED, and to a greater extent higher MVPA are potential behavioral targets for improving pregnancy-specific health-related QoL.

Demographic, Socioeconomic, and Health-Related Predictors of Objectively Measured Sedentary Time and Physical Activity During Pregnancy

BACKGROUND

Sedentary behavior (SED) and moderate-to-vigorous intensity physical activity (MVPA) have important implications for health; however, little is known about predictors of these behaviors during pregnancy.

METHODS

This cohort study measured SED (activPAL) and MVPA (GT3X) in each trimester of pregnancy. Univariate associations of demographic, socioeconomic, and pregnancy health-related factors with SED or MVPA were calculated. Associations with P < .10 were included in stepwise linear regression models to determine independent predictors in each trimester.

RESULTS

Pregnant women (n = 127) were age 31.0 (4.9) years and 78% white. In regression models across trimesters, fewer children ≤ age 5 in the household (P < .04) and primarily sitting job activity (P < .008) were related to higher SED and use of assisted reproductive technology (P < .05) was associated with higher MVPA. In at least one trimester, younger age was related to higher SED (P = .014); no history of pregnancy loss (P < .04), being married (P = .003), employed (P < .004, full time or student), white race (P = .006), and higher education (P = .010) were associated with higher MVPA.

CONCLUSIONS

Predictors of SED in pregnancy were more consistent, and differed from predictors of MVPA. These findings may help identify women at risk of high SED or low MVPA, though future research in larger samples is needed.

Using a consumer-based wearable activity tracker for physical activity goal setting and measuring steps in pregnant women with gestational diabetes mellitus: exploring acceptance and validity

BACKGROUND

Activity monitoring devices may be used to facilitate goal-setting, self-monitoring, and feedback towards a step-based physical activity (PA) goal. This study examined the performance of the wrist-worn Fitbit Charge 3™ (FC3) and sought opinions on walking and stepping-in-place from women with gestational diabetes (GDM).

METHODS

Participants completed six 2-min metronome-assisted over ground bouts that varied by cadence (67, 84, or 100 steps per minute) and mode (walking or stepping-in-place; N = 15), with the sequence randomized. Steps were estimated by FC3 and measured, in duplicate, by direct observation (hand-tally device, criterion). Equivalence testing by the two one-sided tests (TOST) method assessed agreement within ± 15%. Mean absolute percent error (MAPE) of steps were compared to 10%, the accuracy standard of the Consumer Technology Association (CTA)™. A subset (n = 10) completed a timed, 200-m self-paced walk to assess natural walking pace and cadence. All participants completed semi-structured interviews, which were transcribed and analyzed using descriptive and interpretive coding.

RESULTS

Mean age was 27.0 years (SD 4.2), prepregnancy BMI 29.4 kg/m² (8.3), and gestational age 32.8 weeks (SD 2.6). The FC3 was equivalent to hand-tally for bouts of metronome-assisted walking and stepping-in-place at 84 and 100 steps per minute (i.e., P < .05), although walking at 100 steps per minute (P = .01) was no longer equivalent upon adjustment for multiple comparisons (i.e., at P < .007). The FC3 was equivalent to hand-tally during the 200-m walk (i.e., P < .001), in which mean pace was 68.2 m per minute (SD 10.7), or 2.5 miles per hour, and mean cadence 108.5 steps per minute (SD 6.5). For walking at 84 and 100 steps per minute, stepping-in-place at 100 steps per minute, and the 200-m walk, MAPE was within 10%, the accuracy standard of the CTA™. Interviews revealed motivation for PA, that stepping-in-place was an acceptable alternative to walking, and competing responsibilities made it difficult to find time for PA.

CONCLUSIONS

The FC3 appears to be a valid step counter during the third trimester, particularly when walking or stepping-in-place at or close to women's preferred cadence.

Sedentary behaviour and physical activity across pregnancy and birth outcomes

BACKGROUND

Shorter gestation or smaller birth size are indicators of a suboptimal fetal environment and negatively impact short- and long-term offspring health. Understanding how modifiable maternal behaviours, such as moderate-to-vigorous intensity physical activity (MVPA) or sedentary behaviour (SED), improve fetal outcomes could inform strategies to improve health across the lifespan.

OBJECTIVES

The objective of this study was to examine the association of MVPA and SED across pregnancy trimesters on gestational age at delivery and newborn anthropometrics.

METHODS

The MoM Health Study measured SED (thigh-mounted activPAL3 micro) and MVPA (waist-worn Actigraph GTX3) in each trimester of pregnancy. Birth outcomes (gestational age at delivery, birthweight, birth length, and head circumference) were abstracted from medical records and used to calculate ponderal index (grams*100/cm³ ) and size-for-gestational age percentiles. Associations of group-based trajectories and trimester-specific SED and MVPA with birth outcomes were analysed using regression models.

RESULTS

Low, medium, and high trajectory groups were generated SED and MVPA in 103 and 99 pregnant women, respectively. High vs low SED trajectory was associated with earlier gestational age at delivery (β -1.03 weeks, 95% CI -2.01, -0.06), larger head circumference (β 0.83 cm, 95% CI 0.24, 1.63), longer birth length (β 1.37 cm, 95% CI 0.09, 2.64), and lower ponderal index (β -0.24 g*100/cm³ , 95% CI -0.42, -0.06), after adjustment for demographics, pre-pregnancy BMI, and (for newborn anthropometric outcomes) gestational age. The association of high SED with lower ponderal index was the most robust across progressively adjusted models (β -0.25 g*100/cm³ , 95% CI -0.44, -0.07). SED trajectory was not associated with birthweight or size-for-gestational age. High vs low MVPA trajectory was only associated with smaller head circumference (β -0.86 cm, 95% CI -1.70, -0.02).

CONCLUSIONS

Higher SED during pregnancy may result in shorter gestation and inhibited fetal growth. Further research evaluating the effect of reducing SED during pregnancy on birth outcomes is warranted.

Associations of Sleep With Sedentary Behavior and Physical Activity Patterns Across Pregnancy Trimesters

INTRODUCTION

Sleep, sedentary behavior, and moderate-to-vigorous physical activity (MVPA) are altered in pregnancy and may affect pregnancy health; however, how these behaviors are associated with each other is unclear.

METHODS

Pregnant women (N = 120) completed the Pittsburgh Sleep Quality Index and wore an activPAL3 micro and ActiGraph GT3X for 7 days in each trimester to assess sleep, sedentary behavior, and MVPA, respectively. Latent trajectories described patterns of sleep duration, efficiency, and quality as well as sedentary behavior and MVPA. Multinomial logistic regression examined associations of sleep patterns with sedentary behavior and MVPA patterns and, in exploratory analyses, with adverse pregnancy outcomes.

RESULTS

Trajectories were identified for sleep duration (consistently short, 20.7% of sample; consistently adequate, 79.3%), efficiency (consistently low, 17.5%; consistently high, 82.5%), and quality (consistently poor, 15.1%; worsening, 23.5%; and consistently good, 61.5%). Compared with those in more optimal sleep groups, women in the short duration, low efficiency, and worsening quality groups had lower odds of being in the moderate and/or high sedentary behavior group (odds ratio range, 0.21-0.31; 95% confidence interval range, 0.09-0.65). Women in the worsening quality group had greater odds of being in the low MVPA group (odds ratio, 2.51; 95% confidence interval, 1.18-5.38). Trends were observed with women in less optimal sleep groups having greater odds of adverse pregnancy outcomes and lower odds of excessive gestational weight gain.

CONCLUSIONS

Less optimal sleep patterns in pregnancy are associated with less sedentary behavior and MVPA; additional research is needed to confirm associations between sleep and pregnancy outcomes.

Objectively Measured Sedentary Behavior and Physical Activity Across 3 Trimesters of Pregnancy: The Monitoring Movement and Health Study

BACKGROUND

Though moderate- to vigorous-intensity physical activity is recommended, limited research exists on sedentary behavior (SED) during pregnancy.

METHODS

The authors conducted a prospective cohort study to describe objectively measured patterns of SED and activity during each trimester of pregnancy. Women wore thigh- (activPAL3) and waist-mounted (ActiGraph GT3X) activity monitors. SED and activity were compared across trimesters using likelihood ratio tests and described using group-based trajectories. Exploratory analyses associated SED and activity trajectories with adverse pregnancy outcomes and excessive gestational weight gain.

RESULTS

Pregnant women (n = 105; mean [SD] age = 31 [5] y; prepregnancy body mass index = 26.2 [6.6] kg/m2) had mean SED of 9.7, 9.5, and 9.5 hours per day (P = .062) across trimesters, respectively. Some activities differed across trimesters: standing (increased, P = .01), stepping (highest in second trimester, P = .04), steps per day (highest in second trimester, P = .008), and moderate- to vigorous-intensity physical activity (decreased, P < .001). Prolonged SED (bouts ≥ 30 min) and bouted moderate- to vigorous-intensity physical activity (≥10 min) were stable (P > .05). In exploratory analyses, higher SED and lower standing, stepping, and steps per day trajectories were associated with increased odds of adverse pregnancy outcomes (P < .05). No trajectories were associated with excessive gestational weight gain.

CONCLUSIONS

Pregnant women exhibited stable SED of nearly 10 hours per day across pregnancy. Future research evaluating SED across pregnancy and adverse pregnancy outcome risk is warranted.

Toward Harmonized Treadmill-Based Validation of Step-Counting Wearable Technologies: A Scoping Review

BACKGROUND

The authors conducted a scoping review as a first step toward establishing harmonized (ie, consistent and compatible), empirically based best practices for validating step-counting wearable technologies.

PURPOSE

To catalog studies validating step-counting wearable technologies during treadmill ambulation.

METHODS

The authors searched PubMed and SPORTDiscus in August 2019 to identify treadmill-based validation studies that employed the criterion of directly observed (including video recorded) steps and cataloged study sample characteristics, protocol details, and analytical procedures. Where reported, speed- and wear location-specific mean absolute percentage error (MAPE) values were tabulated. Weighted median MAPE values were calculated by wear location and a 0.2-m/s speed increment.

RESULTS

Seventy-seven eligible studies were identified: most had samples averaging 54% (SD = 5%) female and 27 (5) years of age, treadmill protocols consisting of 3 to 5 bouts at speeds of 0.8 (0.1) to 1.6 (0.2) m/s, and reported measures of bias. Eleven studies provided MAPE values at treadmill speeds of 1.1 to 1.8 m/s; their weighted median MAPE values were 7% to 11% for wrist-worn, 1% to 4% for waist-worn, and ≤1% for thigh-worn devices.

CONCLUSIONS

Despite divergent study methodologies, the authors identified common practices and summarized MAPE values representing device step-count accuracy during treadmill walking. These initial empirical findings should be further refined to ultimately establish harmonized best practices for validating wearable technologies.

Validity of self-reported and objectively measured sedentary behavior in pregnancy

Background

Sedentary behavior (SED) is a potential risk factor for poor pregnancy outcomes. We evaluated the validity of several common and one new method to assess SED across three trimesters of pregnancy.

Methods

This cohort study of pregnant women measured objective and self-reported SED each trimester via thigh-worn activPAL3 micro (criterion), waist-worn Actigraph GT3X, and self-report from the Pregnancy Physical Activity Questionnaire (PPAQ) and the de novo Sedentary Behavior Two Domain Questionnaire (SB2D). SED (hours per day) and percent time in SED (SED%) from activPAL were compared to GT3X, SB2D, and PPAQ using Pearson’s r, ICC, Bland-Altman analysis, and comparison of criterion SED and SED% across tertiles of alternative methods.

Results

Fifty-eight women (mean age 31.5 ± 4.8 years; pre-pregnancy BMI 25.1 ± 5.6 kg/m²; 76% white) provided three trimesters of valid activPAL data. Compared to activPAL, GT3X had agreement ranging from r = 0.54–0.66 and ICC = 0.52–0.65. Bland-Altman plots revealed small mean differences and unpatterned errors, but wide limits of agreement (greater than ±2 h and ± 15%). The SB2D and PPAQ had r < 0.5 and ICC < 0.3 vs. activPAL SED, with lower agreement during the 2nd and 3rd trimesters, and performed poorly in Bland-Altman analyses. SED% from the modified SB2D performed best of the self-reported instruments with modest mean differences, r ranging from 0.55 to 0.60, and ICCs from 0.31–0.33; though, limits of agreement were greater than ±35%. Significant trends in activPAL SED were observed across increasing tertiles of SB2D SED in the 1st and 3rd trimesters (both p ≤ 0.001), but not the 2nd trimester (p = 0.425); and for PPAQ SED in the 1st and 2nd trimesters (both p < 0.05), but not the 3rd trimester (p = 0.158). AcitvPAL SED and SED% increased significantly across tertiles of GT3X SED and SED% as well as SB2D SED% (all p-for-trend ≤ 0.001).

Conclusions

Compared to activPAL, waist-worn GT3X produced moderate agreement, though similar mean estimates of SED across pregnancy. Self-report questionnaires had large absolute error and wide limits of agreement for SED hr./day; SB2D measurement of SED% was the best self-report method. These data suggest activPAL be used to measure SED when possible, followed by GT3X, and – when necessary – SB2D assessing SED% in pregnancy.

Trial registration

www.clinicaltrials.govNCT03084302 on 3/20/2017.

Walking for health during pregnancy: A literature review and considerations for future research

Walking is the most commonly chosen type of physical activity (PA) during pregnancy and provides several health benefits to both mother and child. National initiatives have promoted the importance of walking in general, but little emphasis is directed toward pregnant women, the majority of whom are insufficiently active. Pregnant women face a variety of dynamic barriers to a physically active lifestyle, some of which are more commonly experienced during specific times throughout the pregnancy experience. Walking is unique in that it appears resistant to a number of these barriers that limit other types of PA participation, and it can be meaningfully integrated into some transportation and occupational activities when leisure-time options are unavailable. Preliminary intervention work suggests that walking programs can be effectively adopted into a typical pregnancy lifestyle. However, a great deal of work remains to administer successful pregnancy walking interventions, including developing and using validated methods of PA and walking assessment. This narrative review discusses the unique advantages of walking during pregnancy, provides recommendations for future intervention work, and outlines the need for pregnancy-focused community walking initiatives. Standard search procedures were followed to determine sources from the literature specific to walking during pregnancy for use in each section of this review.

Physical Activity Questionnaires for Pregnancy: A Systematic Review of Measurement Properties

Background

In order to assess physical activity (PA) during pregnancy, it is important to choose the instrument with the best measurement properties.

Objectives

To systematically summarize, appraise, and compare the measurement properties of all self-administered questionnaires assessing PA in pregnancy.

Methods

We searched PubMed, Embase, and SPORTDiscus with the following inclusion criteria: (i) the study reported at least one measurement property (reliability, criterion validity, construct validity, responsiveness) of a self-administered questionnaire; (ii) the questionnaire intended to measure PA; (iii) the questionnaire was evaluated in healthy pregnant women; and (iv) the study was published in English. We evaluated results, quality of individual studies, and quality of evidence using a standardized checklist (Quality Assessment of Physical Activity Questionnaires [QAPAQ]) and the GRADE (Grading of Recommendation, Assessment, Development, and Evaluation) approach.

Results

Seventeen articles, reporting 18 studies of 11 different PA questionnaires (17 versions), were included. Most questionnaire versions showed insufficient measurement properties. Only the French and Turkish versions of the Pregnancy Physical Activity Questionnaire (PPAQ) showed both sufficient reliability and construct validity. However, all versions of the PPAQ pooled together showed insufficient construct validity. The quality of individual studies was usually high for reliability but varied considerably for construct validity. Overall, the quality of evidence was very low to moderate.

Conclusions

We recommend the PPAQ to assess PA in pregnancy, although the pooled results revealed insufficient construct validity. The lack of appropriate standards in data collection and processing criteria for objective devices in measuring PA during pregnancy attenuates the quality of evidence. Therefore, research on the validity of comparison instruments in pregnancy followed by consensus on validation reference criteria and standards of PA measurement is needed.

Electronic supplementary material

The online version of this article (10.1007/s40279-018-0961-x) contains supplementary material, which is available to authorized users.

Step-counting accuracy of activity monitors in persons with Down syndrome

BACKGROUND

Accelerometers and pedometers have been used to monitor the number of steps. However, the evidence on the step-counting accuracy of these devices - especially accelerometers - is limited in persons with Down syndrome (DS). This study therefore examined the accuracy of accelerometers placed on the hip or wrist and of a pedometer with a uni-axial accelerometer mechanism in measuring steps in persons with DS and whether device error is associated with walking speed, height, weight, body mass index, waist circumference, leg length, age or sex.

METHOD

Seventeen persons with DS (eight women and nine men; age 33 ± 15 years) walked over-ground for 6 min at their preferred speed. The steps were measured with a hip-worn and a wrist-worn ActiGraph accelerometer using the manufacturer's default (DF) and low-frequency extension (LFE) filters, and with the NL-1000 New Lifestyles pedometer on the hip. Steps were also measured with hand tally which served as the criterion.

RESULTS

Absolute percent error was considerable and differed statistically between devices (P = 0.001); however, error improved for accelerometers when LFE was applied (Hip-DF: 31.6 ± 18.8%; Hip-LFE: 9.7 ± 12.8%; Wrist-DF: 32.7 ± 14.2%; Wrist-LFE: 13.6 ± 10.2%; Pedometer: 23.2 ± 22.8%). Bland-Altman plots indicated underestimation of steps for accelerometers and the pedometer. Application of LFE, however, improved the prediction of the accelerometers. The number of steps measured by the hip accelerometer with LFE and by the pedometer did not differ statistically from actual steps. Steps by the remaining methods were significantly lower than hand tally (P ≤ 0.001). Correlations between percent error for each device and walking speed, anthropometry, age or sex ranged between -0.28 and +0.48, and were non-significant, except for age.

CONCLUSIONS

The results demonstrated that the pedometer and ActiGraph accelerometers have considerable error in measuring steps of persons with DS. Application of LFE, however, significantly improved the step-counting performance of the Actigraph accelerometers.

Physical Activity Device Reliability and Validity during Pregnancy and Postpartum

Current physical activity (PA) recommendations for women experiencing a normal pregnancy reflect recent research showing numerous health benefits for mother and offspring. However, few studies have evaluated PA devices' reliability and validity during pregnancy, because anatomical and physiological changes throughout gestation could affect an instrument's accuracy.

PURPOSE

This study aimed to determine the reliability and validity of PA devices worn on the hip, ankle, and triceps during pregnancy and postpartum.

METHODS

Thirty-three women performed six activities of daily living and one treadmill walk at approximately 21 and 32 wk of pregnancy, and 12 wk postpartum. There were two visits at each time period, 1 wk apart. Energy expenditure (oxygen consumption) was measured by using indirect calorimetry (IC; criterion measure), whereas PA was quantified by using accelerometers and pedometers placed at the right hip and ankle and left triceps. Interclass reliability and monitor validity compared with IC in relative (mL·kg·min) terms were calculated using Pearson correlation. Both multitrial and single-trial intraclass reliabilities (ICC) were estimated using ANOVA to assess monitor reliability at each time period. SEM values were calculated in relative terms for each time period.

RESULTS

The reliability of the devices was moderate/strong because 66% of the Pearson correlations were between 0.6 and 1.0. Multitrial ICC values were largely in the moderate/strong range because 38% of the ICC values were between 0.6 and 0.79 and 50% were between 0.8 and 1.0. The SEM values for each device between visits ranged from 7% to 23% of the mean values. Comparison between IC and devices showed that 40% and 46% of the validity coefficients were between 0.4 and 0.59 and between 0.6 and 0.79, respectively.

CONCLUSIONS

PA devices show moderate/strong reliability and moderate validity for measuring PA during pregnancy and postpartum.

A systematic literature review of reviews on techniques for physical activity measurement in adults: a DEDIPAC study

The links between increased participation in Physical Activity (PA) and improvements in health are well established. As this body of evidence has grown, so too has the search for measures of PA with high levels of methodological effectiveness (i.e. validity, reliability and responsiveness to change). The aim of this “review of reviews” was to provide a comprehensive overview of the methodological effectiveness of currently employed measures of PA, to aid researchers in their selection of an appropriate tool. A total of 63 review articles were included in this review, and the original articles cited by these reviews were included in order to extract detailed information on methodological effectiveness.

Self-report measures of PA have been most frequently examined for methodological effectiveness, with highly variable findings identified across a broad range of behaviours. The evidence-base for the methodological effectiveness of objective monitors, particularly accelerometers/activity monitors, is increasing, with lower levels of variability observed for validity and reliability when compared to subjective measures. Unfortunately, responsiveness to change across all measures and behaviours remains under-researched, with limited information available.

Other criteria beyond methodological effectiveness often influence tool selection, including cost and feasibility. However, researchers must be aware of the methodological effectiveness of any measure selected for use when examining PA. Although no “perfect” tool for the examination of PA in adults exists, it is suggested that researchers aim to incorporate appropriate objective measures, specific to the behaviours of interests, when examining PA in free-living environments.

Postprandial walking reduces glucose levels in women with gestational diabetes mellitus

The purpose of this study was to investigate blood glucose changes, as measured by a continuous glucose monitoring system, that occur in women with gestational diabetes mellitus (GDM) following an acute bout of moderate-intensity walking after consuming a high-carbohydrate/low-fat meal. This study found that moderate-intensity walking induced greater postprandial glucose control compared with sedentary activity and it appears that moderate-intensity activity may be used to reduce postprandial glucose levels in women with GDM.

Do changing levels of maternal exercise during pregnancy affect neonatal adiposity? Secondary analysis of the babies after SCOPE: evaluating the longitudinal impact using neurological and nutritional endpoints (BASELINE) birth cohort (Cork, Ireland)

OBJECTIVE

To investigate whether changing levels of exercise during pregnancy are related to altered neonatal adiposity.

DESIGN

Secondary analysis of data from a prospective cohort study.

SETTING

Cork, Ireland.

PARTICIPANTS

1200 mother - infant pairs recruited as part of a prospective birth cohort, Babies After SCOPE: Evaluating the Longitudinal Impact Using Neurological and Nutritional Endpoints (BASELINE).

MAIN OUTCOME MEASURES

Neonatal adiposity was assessed within several days of birth using air displacement plethysmography (PEAPOD). Per cent body fat (BF%) as a continuous outcome and a pair of dichotomous variables; high or low adiposity, representing BF% >90th or <10th centile, respectively. Multivariable linear and logistic regression models were used to investigate the relationship between exercise and the respective outcomes.

RESULTS

Crude analysis revealed no association between a changing level of exercise (since becoming pregnant) at 15 weeks' gestation and any of the outcomes (BF%, low adiposity and high adiposity). At 20 weeks' gestation, analyses revealed that relative to women who do not change their exercise level up to 20 weeks, those women who decreased their exercise level were more likely to give birth to a neonate with adiposity above the 90th centile (OR 1.62, 95% CI 1.07 to 2.46). This association was maintained after adjustment for putative confounders (OR 1.62, 95% CI 1.06 to 2.47).

CONCLUSIONS

We observed a possible critical period for the association between changing exercise levels and neonatal adiposity, with no association observed with exercise recall for the first 15 weeks of gestation, but an association with a decreasing level of exercise between 15 and 20 weeks. These results should be interpreted in line with the limitations of the study and further studies utilising objectively measured estimates of exercise are required in order to replicate these findings.

TRIAL REGISTRATION NUMBER

NCT01498965.

Sedentary and Physical Activity Patterns in Adults with Intellectual Disability

Little is known about the patterns of sedentary time (ST) and physical activity (PA) levels throughout the week among adults and older adults with Intellectual Disability (ID). We analyzed ST and PA patterns of adults and older adults with ID. Forty-two adults and 42 older adults with mild to severe ID participated in this study. Height and weight were obtained to calculate Body Mass Index (BMI). Body fat and fat-free mass percentages were also obtained. Patterns of PA levels and ST were assessed with GT3X Actigraph accelerometers. Adults performed higher amounts of total PA and moderate to vigorous PA than older adults during the week, on weekdays and in center time (all p > 0.05). No differences between males and females were found for either PA levels or ST. Only 10.7% of the participants met the global recommendations on PA for health. The participants of the current study showed low PA levels and a high prevalence of ST. Interestingly, when comparing age and/or sex groups, no differences were observed for ST. Our findings provide novel and valuable information to be considered in future interventions aiming to increase PA levels and reduce ST.

Sedentary behavior patterns in non-pregnant and pregnant women

Sedentary behavior has been associated with adverse health outcomes among pregnant women; however, few studies have characterized sedentary behavior patterns in this population. We described patterns of accelerometer-determined indicators of sedentary behavior among a national sample of US pregnant (n = 234) women and non-pregnant (n = 1146) women participating in the NHANES 2003-06 cycles. We included women with ≥ 4 days of accelerometer wear of ≥ 10 h/day. A count threshold of < 100 cpm was used to describe sedentary behavior as: 1) total accumulated sedentary time by bout length categories; 2) accumulated sedentary time within discrete bout length categories; 3) mean, median, and usual bout length; and 4) and bout frequency. Both non-pregnant and pregnant women spent up to 60% of their accelerometer wear time in sedentary behavior depending on the minimum bout threshold applied. Sedentary time was higher among pregnant women compared to non-pregnant women when lower bout thresholds (i.e. 10 min or less) were applied. The majority of total sedentary time was accumulated in bouts lasting < 10 min. The women averaged less than two prolonged sedentary bouts (i.e., ≥ 30 min) per day, which accounted for nearly 20% of total accumulated sedentary time. When applying a minimum threshold of at least 15 min, sedentary time increased across pregnancy trimesters, while sedentary time was similar across trimesters when using lower thresholds. These findings provide the first characterization of accelerometer-determined indicators of sedentary behavior in pregnant women. The minimum bout threshold applied influenced estimates of sedentary time and patterns sedentary time accumulation across pregnancy trimesters.

•

How we operationalized sedentary behavior affects estimates of sedentary time.

•

How women accumulate their sedentary time, changes over trimesters of pregnancy.

•

Most sedentary bouts are short in duration (i.e. < 10 min).

•

Long sedentary bouts (i.e. ≥ 30 min) account for ~ 20% of total sedentary time.

Comparison between Mother, ActiGraph wGT3X-BT, and a hand tally for measuring steps at various walking speeds under controlled conditions

Introduction

Walking is endorsed as health enhancing and is the most common type of physical activity among older adults. Accelerometers are superior to self-reports when measuring steps, however, if they are to be used by clinicians the validity is of great importance. The aim of this study was to investigate the criterion validity of Mother and ActiGraph wGT3X-BT in measuring steps by comparing the devices to a hand tally under controlled conditions in healthy participants.

Methods

Thirty healthy participants were fitted with a belt containing the sensor of Mother (Motion Cookie) and ActiGraph. Participants walked on a treadmill for two minutes at each of the following speeds; 3.2, 4.8, and 6.4 km/h. The treadmill walking was video recorded and actual steps were subsequently determined by using a hand tally. Wilcoxon’s signed ranks test was used to determine whether Mother and ActiGraph measured an identical number of steps compared to the hand tally. Intraclass correlation coefficients were calculated to determine the relationship and Root Mean Square error was calculated to investigate the average error between the devices and the hand tally. Percent differences (PD) were calculated for between-instrument agreement (Mother vs. the hand tally and ActiGraph vs. the hand tally) and PDs below 3% were interpreted as acceptable and clinically irrelevant.

Results

Mother and ActiGraph under-counted steps significantly compared to the hand tally at all walking speeds (p < 0.001). Mother had a median of total differences of 9.5 steps (IQR = 10) and ActiGraph 59 steps (IQR = 77). Mother had smaller PDs at all speeds especially at 3.2 km/h (2.5% compared to 26.7%). Mother showed excellent ICC values ≥0.88 (0.51–0.96) at all speeds whilst ActiGraph had poor and fair to good ICC values ranging from 0.03 (−0.09–0.21) at a speed of 3.2 km/h to 0.64 (0.16–0.84) at a speed of 6.4 km/h.

Conclusion

Mother provides valid measures of steps at walking speeds of 3.2, 4.8, and 6.4 km/h with clinically irrelevant deviations compared to a hand tally while ActiGraph only provides valid measurements at 6.4 km/h based on the 3% criterion. These results have significant potential for valid objective measurements of low walking speeds. However, further research should investigate the validity of Mother in patients at even slower walking speeds and in free-living conditions.

Application of objective physical activity measurement in an antenatal physical activity consultation intervention: a randomised controlled trial

BACKGROUND

Physical Activity (PA) during pregnancy has many health benefits, however, inactivity in this population is common and PA often declines with increasing gestation. PA consultations have been useful in promoting PA in the general population, however their use for addressing PA in pregnancy is unknown. This study aimed to examine if a theory-based intervention using PA consultations would reduce the magnitude of decline in objectively measured PA between the first and third trimesters of pregnancy.

METHODS

A RCT was carried out in an urban maternity unit in Northern Ireland between September 2012 and June 2013. 109 low-risk, primigravida pregnant women were randomised to a control (n = 54) or intervention group (n = 55). Intervention participants received three face-to-face individual PA consultations. Daily PA was measured in each trimester using seven day accelerometry. The study was approved by a NHS trust (12/NI/0036). PA data in counts per minute (CPM) were categorised into intensity using Freedson cut points and mean minutes of PA were compared between groups using repeated measures ANOVA with a sub-analysis stratifying participants per PA level in trimester one.

RESULTS

Intention to treat analysis was performed on data from 97 participants. Time in moderate, vigorous and moderate-vigorous intensity PA (MVPA) significantly declined between trimesters one and three in both groups (P < 0.001). There were no statistically significant differences in PA between groups in any trimester. Women in the intervention group who were less active in trimester one did not demonstrate a significant decline in MVPA throughout pregnancy (in contrast with the decline identified in the more active participants).

CONCLUSIONS

The findings indicate that PA consultations were not effective in reducing the decline of MVPA in throughout pregnancy, however, women who were less active in trimester one and received PA consultations had a lesser decrease in MVPA. It is possible that pregnant women, specifically those who are more active at the start of pregnancy, have differing needs for PA behaviour change and maintenance, requiring more intense interventions than less active women.

TRIAL REGISTRATION

Current Controlled Trials Register ISRCTN61829137.

Physical activity, depressed mood and pregnancy worries in European obese pregnant women: results from the DALI study

BACKGROUND

The purpose of this study was to examine the association between mental health status (i.e. depressed mood and pregnancy-related worries) and objectively measured physical activity levels in obese pregnant women from seven European countries.

METHODS

Baseline data from the vitamin D and lifestyle intervention for the prevention of gestational diabetes mellitus (DALI) study were used. Time spent in moderate-to-vigorous physical activity (MVPA) and sedentary behaviour was measured with accelerometers. Depressed mood was measured with the WHO well-being index (WHO-5) and pregnancy-related worries with the Cambridge Worry Scale (CWS). In addition, socio-demographic characteristics, lifestyle factors, and perceptions and attitude regarding weight management and physical activity were measured. Linear regression analyses were performed to assess the association of mental health status with MVPA and sedentary behaviour.

RESULTS

A total of 98 obese pregnant women from Austria, Belgium, Ireland, Italy, Poland, Spain and the Netherlands were included. Women had a mean age of 31.6 ± 5.8 years, a pre-pregnancy BMI of 34.1 ± 4.3 kg/m(2), and were on average 15.4 ± 2.8 weeks pregnant. WHO-5 scores indicative of depressed mood (<50) were reported by 27.1 % of the women and most frequently endorsed pregnancy-related worries pertained to own and the baby's health. Women with good well-being spent 85% more time in MVPA compared to women with a depressed mood (P = 0.03). No differences in MVPA levels were found for women with no, some, or many pregnancy worries. Depressed mood and pregnancy-related worries were not associated with sedentary behaviour.

CONCLUSIONS

These findings suggest that in pregnant women who are obese, a depressed mood, but not pregnancy-related worries, may be associated with less physical activity. The combined risk of poor mental health and low physical activity levels makes women vulnerable for pregnancy complications. Whether a depressed mood may be a barrier for improving physical activity warrants further study.

Pattern changes in step count accumulation and peak cadence due to a physical activity intervention

OBJECTIVES

The purpose was to determine if a 12-week weight loss intervention with a physical activity (PA) component would lead to changes in steps/day, step count accumulation patterns, and peak cadence.

DESIGN

Randomized clinical trial.

METHODS

Overall, 121 overweight/obese White and African-American adults (ages 35-64yrs) were randomized to a diet education plus PA education and behavior change intervention group (DE+PA) or diet education and behavior change group (DE). The DE+PA intervention was designed to increase steps/day, and steps at moderate-to-vigorous intensity. The Actigraph GT3X+ accelerometer was used to measure steps accumulated in different cadence bands (1-19, 20-39, 40-59, 60-79, 80-99, 100-119, 120+ steps/min), and peak 1-min, 30-min and 60-min cadence. Pre- to post-intervention changes in steps/day, step count within each cadence band, and peak cadences were compared within groups using paired sample t-test and between groups after adjustment for baseline values of the same variable using ANCOVA.

RESULTS

Ninety participants had valid data (44 in the DE+PA group). Change in steps/day was not significantly different between the groups. However, participants in the DE+PA group accumulated significantly more steps at post-intervention in the 80-99, 100-119, and 120+ cadence bands, all p<0.02. The DE+PA group increased step counts accumulated within the 100-119 (463±1092 vs 56±546 step counts; p=0.01) and 120+ (390±999 vs 34±321 step counts; p=0.03) cadence bands, as well as peak 60-min cadence when compared to the DE group.

CONCLUSIONS

Non-significant changes in steps/day following a PA intervention may mask changes in steps accumulated at moderate-to-vigorous intensity cadences.

The relationship of objectively measured physical activity and sedentary behaviour with gestational weight gain and birth weight

Objective. To evaluate the relationship of physical activity (PA) and sedentary behaviour with gestational weight gain (GWG) and birth weight. Design. Combined data from two prospective studies: (1) nulliparous pregnant women without BMI restrictions and (2) overweight and obese pregnant women at risk for gestational diabetes. Methods. Daily PA and sedentary behaviour were measured with an accelerometer around 15 and at 32–35 weeks of gestation. The association between time spent in moderate-to-vigorous PA (MVPA) and in sedentary activities with GWG and birth weight was determined. Main outcome measures were GWG between 15 and 32 weeks of gestation, average GWG per week, and birth weight. Results. We studied 111 women. Early in pregnancy, 32% of women spent ≥30 minutes/day in at least moderate PA versus 12% in late pregnancy. No significant associations were found between time spent in MVPA or sedentary behaviour with GWG or birth weight. Conclusions. We found no relation between MVPA and sedentary behaviour with GWG or birth weight. The small percentage of women meeting the recommended levels of PA indicates the need to inform and support pregnant women to maintain regular PA, as there seems to be no adverse effect on birth weight and maintaining PA increases overall health.

Effects of filter choice in GT3X accelerometer assessments of free-living activity

PURPOSE

ActiGraph accelerometers are widely used devices to objectively assess physical activity. The GT3X version has two filter options to be selected before data assessment (normal and low-frequency extension filter option). It is not clear whether the resulting physical activity levels differ depending on the choice of the filter. The aims were to compare GT3X data collected using the different filter options during free-living activities and to establish correction factors if the results were not comparable.

METHODS

Sixty-five participants of the population-based SAPALDIA-cohort (50.8% women, age range = 40-80 yr) wore two GT3X accelerometers with different filter selections simultaneously during 8 d. Spearman correlations, Wilcoxon rank sum tests, McNemar tests, scatter plots, and Bland-Altman plots were used to compare the data. Correction factors were established using linear regression models.

RESULTS

Although Spearman correlations were high (r ≥ 0.93), there were significant differences in minutes per day between filter options for nonwearing time and time spent in sedentary, light, and moderate-to-vigorous physical activity (all P < 0.001), with more remarkable differences in the lower range of activity (sedentary and light activities). Mean counts per minute and steps per day were significantly higher using the low-frequency extension filter (P < 0.001). Most differences could be resolved using the correction factors.

CONCLUSIONS

The observed differences are especially important when research is focusing on sedentary and light activities. In future studies, it is important to carefully evaluate the suitable filter option and to specify the filter choice in publications. The correction factors can be used to make data assessed using the low-frequency extension filter comparable to data assessed using the normal filter option.

Physical activity and pregnancy: past and present evidence and future recommendations

PURPOSE

In this review, we provide researchers and practitioners with an overview of the physical activity and pregnancy literature to promote prenatal physical activity, improve measurement, further elucidate the role of activity in reducing maternal health complications, and inform future research.

METHOD

We examined past and present physical activity and pregnancy studies and highlight key papers with a focus on maternal health outcomes to best inform physical activity promotion efforts.

RESULTS

We discuss: (a) historical overview of prenatal physical activity relative to the physical activity guidelines, how they have changed over time, and how evidence of the effect of prenatal activity on maternal/fetal health outcomes has affected clinical recommendations; (b) existing tools and challenges associated with measuring prenatal physical activity; (c) empirical evidence on multilevel determinants of prenatal activity to guide future intervention work; (d) empirical evidence of prenatal activity on adverse maternal outcomes (gestational diabetes mellitus, preeclampsia, excessive gestational weight gain) from observational and intervention studies; and (e) summary/recommendations for future research and practice.

CONCLUSIONS

The physical activity and pregnancy literature has evolved over the past 50 years, and there is sufficient empirical evidence to support the promotion of moderate-to-vigorous prenatal physical activity for maternal health benefits. Future studies and interventions should be carefully designed, theoretically driven, and include validated and reliable activity measures. Researchers and practitioners should also consider the multifaceted determinants and outcomes of prenatal physical activity and intervene to promote physical activity before, during, and after pregnancy.

Comparison of older adults' steps per day using NL-1000 pedometer and two GT3X+ accelerometer filters

The purpose of this study was to compare the steps/d derived from the ActiGraph GT3X+ using the manufacturer's default filter (DF) and low-frequency-extension filter (LFX) with those from the NL-1000 pedometer in an older adult sample. Fifteen older adults (61-82 yr) wore a GT3X+ (24 hr/day) and an NL-1000 (waking hours) for 7 d. Day was the unit of analysis (n = 86 valid days) comparing (a) GT3X+ DF and NL-1000 steps/d and (b) GT3X+ LFX and NL-1000 steps/d. DF was highly correlated with NL-1000 (r = .80), but there was a significant mean difference (-769 steps/d). LFX and NL-1000 were highly correlated (r = .90), but there also was a significant mean difference (8,140 steps/d). Percent difference and absolute percent difference between DF and NL-1000 were -7.4% and 16.0%, respectively, and for LFX and NL-1000 both were 121.9%. Regardless of filter used, GT3X+ did not provide comparable pedometer estimates of steps/d in this older adult sample.

Device-based monitoring in physical activity and public health research

Measurement of physical activity is important, given the vital role of this behavior in physical and mental health. Over the past quarter of a century, the use of small, non-invasive, wearable monitors to assess physical activity has become commonplace. This review is divided into three sections. In the first section, a brief history of physical activity monitoring is provided, along with a discussion of the strengths and weaknesses of different devices. In the second section, recent applications of physical activity monitoring in physical activity and public health research are discussed. Wearable monitors are being used to conduct surveillance, and to determine the extent and distribution of physical activity and sedentary behaviors in populations around the world. They have been used to help clarify the dose-response relation between physical activity and health. Wearable monitors that provide feedback to users have also been used in longitudinal interventions to motivate research participants and to assess their compliance with program goals. In the third section, future directions for research in physical activity monitoring are discussed. It is likely that new developments in wearable monitors will lead to greater accuracy and improved ease-of-use.

Validation and responsiveness of the AQuAA for measuring physical activity in overweight and obese pregnant women

OBJECTIVES

The aim of this study was to assess the validity and responsiveness of the self-report Activity Questionnaire for Adults and Adolescents for use in overweight and obese pregnant women.

DESIGN

Longitudinal study with measurements at 17, 24 and 32 weeks of pregnancy.

METHODS

Overweight and obese pregnant women (n=55) were asked to wear an accelerometer (Actigraph model ActiTrainer) and fill out the AQuAA at 17, 24 and 32 weeks of pregnancy. AQuAA outcomes were compared with objective accelerometer data. With accelerometer data, different cut-off points of counts per minute were used to define light, moderate and vigorous physical activities. Spearman correlation coefficients were used to assess evidence for construct validity and responsiveness.

RESULTS

Compared with the accelerometer, time spent in moderate and vigorous physical activities was higher according to the questionnaire, while time spent in sedentary activity was lower. The correlations between AQuAA and accelerometer data were small, regardless of which cut-off point for intensity was used.

CONCLUSIONS

Overweight and obese pregnant women overestimated the time spent in physical activities and underestimated the time spent in sedentary behaviours. The construct validity and responsiveness of the AQuAA compared to an accelerometer was poor for these overweight and obese pregnant women.

Validity of activity monitors in health and chronic disease: a systematic review

The assessment of physical activity in healthy populations and in those with chronic diseases is challenging. The aim of this systematic review was to identify whether available activity monitors (AM) have been appropriately validated for use in assessing physical activity in these groups. Following a systematic literature search we found 134 papers meeting the inclusion criteria; 40 conducted in a field setting (validation against doubly labelled water), 86 in a laboratory setting (validation against a metabolic cart, metabolic chamber) and 8 in a field and laboratory setting. Correlation coefficients between AM outcomes and energy expenditure (EE) by the criterion method (doubly labelled water and metabolic cart/chamber) and percentage mean differences between EE estimation from the monitor and EE measurement by the criterion method were extracted. Random-effects meta-analyses were performed to pool the results across studies where possible. Types of devices were compared using meta-regression analyses. Most validation studies had been performed in healthy adults (n = 118), with few carried out in patients with chronic diseases (n = 16). For total EE, correlation coefficients were statistically significantly lower in uniaxial compared to multisensor devices. For active EE, correlations were slightly but not significantly lower in uniaxial compared to triaxial and multisensor devices. Uniaxial devices tended to underestimate TEE (−12.07 (95%CI; -18.28 to −5.85) %) compared to triaxial (−6.85 (95%CI; -18.20 to 4.49) %, p = 0.37) and were statistically significantly less accurate than multisensor devices (−3.64 (95%CI; -8.97 to 1.70) %, p<0.001). TEE was underestimated during slow walking speeds in 69% of the lab validation studies compared to 37%, 30% and 37% of the studies during intermediate, fast walking speed and running, respectively. The high level of heterogeneity in the validation studies is only partly explained by the type of activity monitor and the activity monitor outcome. Triaxial and multisensor devices tend to be more valid monitors. Since activity monitors are less accurate at slow walking speeds and information about validated activity monitors in chronic disease populations is lacking, proper validation studies in these populations are needed prior to their inclusion in clinical trials.

Physical activity among postpartum adolescents: a preliminary report

The purpose of this study was to examine the levels and correlates of physical activity among a sample of overweight postpartum adolescents. Postpartum adolescents were recruited from a university-based teen mother program and local school districts. Adolescents (N = 21) aged 16 to 19 years, with a child between 6 and 12 months of age, volunteered. Participants wore a pedometer and reported their physical activity for seven consecutive days. Descriptive statistics and relationships between steps/day and self-reported physical activity, demographic, and psychosocial characteristics were calculated. Results indicated that participants were insufficiently active. Self-reported walking and pre-pregnancy BMI were moderately associated with steps/day. The findings of this preliminary study suggest that these postpartum adolescents were insufficiently active to attain substantial health benefits from physical activity. Postpartum adolescents represent an understudied population that may need to be a priority population for physical activity interventions.

Accuracy of physical activity assessment during pregnancy: an observational study

Background

Prenatal physical activity may improve maternal and infant health and lower future disease risk for both mother and baby; however, very few physical activity assessment methods have been validated for use during pregnancy. The purpose of this study was to evaluate the accuracy of a subjective physical activity record (PAR) and an objective activity monitor, against a reference standard to quantify moderate and vigorous physical activity (MVPA) in pregnant women. The reference standard was based on participant interviews to determine if a woman was an exerciser and confirmed with information obtained from the PAR and a heart rate monitor.

Methods

Fifty-two pregnant women completed a physical activity record (PAR) and wore a SenseWear^® Mini Armband (SWA) activity monitor over a 7-day period at 18 weeks gestation. Total minutes spent in MVPA were totaled from both modalities and evaluated against the reference standard using contingency analysis and Pearson's chi-square test to evaluate the number of women meeting minimum prenatal physical activity recommendations (at least 3, 30 minute sessions of exercise per week). Both modalities were also tested individually and collectively to assess their ability as indicators of activity using empirically determined cut-offs as indicated by receiver-operator characteristic curves. These experimentally-derived criteria were also tested with Pearson's chi-square test.

Results

According to the reference standard, 13 of 52 participants (25%) met the criterion of 3, 30 minute sessions of volitional, moderate-intensity activity. When compared to the reference standard, both the PAR and SWA overestimated exercise status; 42 (81%) and 52 (100%) participants, respectively, achieved 90 minutes of MVPA (P < 0.0001 for both comparisons). Single-modality predictors of MVPA did not show a significant correlation. A composite predictor of MVPA offered the most favorable option for sensitivity and specificity (true positives, n = 8 and true negatives, n = 36) using cut-offs of 280 and 385 minutes/week for the PAR and SWA, respectively.

Conclusion

Compared to the reference standard, time spent in MVPA obtained from the PAR or SWA overestimated the prevalence of women meeting prenatal exercise recommendations. The most accurate predictor of women meeting current prenatal exercise guidelines was identified by using the PAR and SWA collectively.

Agreement between pedometer and accelerometer in measuring physical activity in overweight and obese pregnant women

BACKGROUND

Inexpensive, reliable objective methods are needed to measure physical activity (PA) in large scale trials. This study compared the number of pedometer step counts with accelerometer data in pregnant women in free-living conditions to assess agreement between these measures.

METHODS

Pregnant women (n = 58) with body mass index ≥25 kg/m(2) at median 13 weeks' gestation wore a GT1M Actigraph accelerometer and a Yamax Digi-Walker CW-701 pedometer for four consecutive days. The Spearman rank correlation coefficients were determined between pedometer step counts and various accelerometer measures of PA. Total agreement between accelerometer and pedometer step counts was evaluated by determining the 95% limits of agreement estimated using a regression-based method. Agreement between the monitors in categorising participants as active or inactive was assessed by determining Kappa.

RESULTS

Pedometer step counts correlated moderately (r = 0.36 to 0.54) with most accelerometer measures of PA. Overall step counts recorded by the pedometer and the accelerometer were not significantly different (medians 5961 vs. 5687 steps/day, p = 0.37). However, the 95% limits of agreement ranged from -2690 to 2656 steps/day for the mean step count value (6026 steps/day) and changed substantially over the range of values. Agreement between the monitors in categorising participants to active and inactive varied from moderate to good depending on the criteria adopted.

CONCLUSIONS

Despite statistically significant correlations and similar median step counts, the overall agreement between pedometer and accelerometer step counts was poor and varied with activity level. Pedometer and accelerometer steps cannot be used interchangeably in overweight and obese pregnant women.

Physical activity monitor for recording energy expenditure in pregnancy

OBJECTIVE

To determine whether the energy expenditure recorded with the physical activity monitor SenseWear™ Pro(2) Armband differs from that recorded with indirect calorimetry.

DESIGN

Cross-sectional comparison of measures of energy expenditure.

SETTING

A convenient sample recruited from a randomized controlled trial.

POPULATION

Twenty-nine pregnant women (24-43 years old).

METHODS

Energy expenditure was recorded with SenseWear™ Pro(2) Armband and a portable oxygen analyzer for 90 minutes while carrying out a variety of activities of different intensities.

MAIN OUTCOME MEASURES

Energy expenditure recorded with the physical activity monitor SenseWear™ Pro(2) Armband.

RESULTS

Comparing energy expenditure during free-living activities, the mean differences and limits of agreements from Bland-Altman plots was -136±343 kJ, giving an underestimation of energy expenditure by 9%. The intraclass correlation coefficient was 0.85 (95% confidence interval 0.71-0.93; p<0.001), giving 85% of the variance explained by differences among individuals.

CONCLUSIONS

SenseWear™ Pro(2) Armband is a valid measure of energy expenditure during pregnancy.