Christopher P. Connolly

Physiologic Responses to Running with a Jogging Stroller

The purpose of this study was to assess the effect of running with a jogging stroller (JS) on oxygen consumption (VO2), heart rate (HR), and rating of perceived exertion (RPE). This study included 2 parts: Part 1 involved participants (N=15) running on an indoor track and Part 2 involved participants (N=12) running on a paved greenway. All participants completed 6, one-mile trials randomized over 2 visits: 3 were completed at a predetermined pace (160.8 m·min (- 1)) without a JS (NoJS), with 11.36 kg in the JS (JS1), and 22.72 kg in the JS (JS2) and 3 were self-paced and included NoJS, JS1, and JS2. VO2 and HR were measured using a portable metabolic system and telemetry. Repeated measures ANOVAs were used to determine differences among conditions. Part 1, there were no differences in VO2 across conditions, but HR and RPE were significantly higher (P<0.05) during the JS trials compared to the NoJS trials. Part 2, VO2 and RPE during JS trials were higher than NoJS trials (P<0.05). No significant differences were found in HR. The results indicate that it is feasible to run while pushing a JS with minimal increases in exertion compared to running without a JS.

A comparison of methods to determine center of mass during pregnancy

Balance changes during pregnancy likely occur because of mass gains and mass distribution changes. However, to date there is no way of tracking balance through center of mass motion because no method is available to identify of the body center of mass throughout pregnancy. We compared methods for determining segment masses and torso center of mass location. The availability of a method for tracking these changes during pregnancy will make determining balance changes through center of mass motion an option for future pregnancy balance research. Thirty pregnant women from eight weeks gestation until birth were recruited for monthly anthropometric measurements, motion capture analysis of body segment locations, and force plate analysis of center of pressure during quiet standing and supine laying. From these measurements, we were able to compare regression, volume measurement, and weighted sum methods to calculate body center of mass throughout pregnancy. We found that mass changes around the trunk were most prevalent as expected, but mass changes throughout the body (especially the thighs) were also seen. Our findings also suggest that a series of anthropometric measurements first suggested by Pavol et al. (2002), in combination with quiet standing on a force plate, can be used to identify the needed components (segment masses and torso center of mass location in three dimensions) to calculate body center of mass changes during pregnancy. The results of this study will make tracking of center of mass motion a possibility for future pregnancy balance research.

The Influence of Risk Perceptions and Efficacy Beliefs on Leisure-Time Physical Activity During Pregnancy

BACKGROUND Pregnancy risk perceptions and physical activity efficacy beliefs may facilitate or impede pregnancy leisure-time physical activity (LTPA). We examined the separate and joint influence of these variables on LTPA behavior among pregnant women. METHODS Pregnant women (n = 302) completed a survey containing questions on LTPA efficacy beliefs and behavior, as well as pregnancy risk perceptions with respect to the health of the unborn baby. As stipulated by the Risk Perception Attitude (RPA) Framework, 4 attitudinal groups were created: Responsive (High Risk+High Efficacy), Proactive (Low+High), Avoidant (High+Low), and Indifferent (Low+Low). Moderate LTPA and vigorous LTPA were dichotomized for study analyses. RESULTS A total of 82 women (27.2%) met the moderate physical activity guideline and 90 women (30.1%) performed any vigorous LTPA. Responsive and proactive pregnant women (those with high efficacy) were most likely to meet the moderate guideline and participate in vigorous LTPA. Hierarchical logistic regression did not reveal an interactive effect of pregnancy risk perceptions and LTPA efficacy beliefs for meeting the moderate guideline (OR = 0.94, 95% CI = 0.66-1.36) or any vigorous LTPA participation (OR = 1.41, 95% CI = 0.86-2.29). CONCLUSIONS LTPA efficacy beliefs appear important in facilitating greater levels of pregnancy LTPA. Significant interactive effects between pregnancy risk perceptions and LTPA efficacy beliefs were not found.

Walking balance on a treadmill changes during pregnancy

BACKGROUND Altered standing balance during pregnancy has been previously reported. To date, body center of mass (bCOM) motion has not been used to track balance changes in this population. We recently compared three methods to determine the torso center of mass (tCOM) location (via force plate acquired center of pressure calculation, using Pavol surface anthropometry measurements, and a combination of the two) to use in calculating the bCOM during pregnancy. RESEARCH QUESTION This current research explored two questions: (1) does walking balance change during pregnancy, and (2) do the methods for identifying tCOM location affect the resulting balance measures? METHODS Fifteen pregnant women were recruited to perform 60-second trial of treadmill walking at 4-week intervals from 12 weeks gestation until delivery. Walking balance was measured as bCOM motion within the base of support. Gestation time and anthropometric model (force plate, Pavol, and combination) were repeated-measures independent variables in a general linear mixed model analysis. RESULTS There was a significant decrease in walking balance during pregnancy. As gestation progressed, we observed non-linear changes in the bCOM motion within the base of support over time, with some changes starting early in pregnancy and others not starting until late 2nd trimester. The anthropometric model used to locate the bCOM significantly influences balance measures. The results of this study indicate that the force plate method is more appropriate for locating the tCOM in the anterior and lateral directions. SIGNIFICANCE The results of this study will inform clinicians and patients about the gestational stage-associated changes in balance during pregnancy that increase the risk of falling and injury. Researchers should also carefully consider the method for locating the bCOM.

Resist Forgetting: Effects of Aerobic and Resistance Exercise on Prospective and Retrospective Memory.

Previous research indicates that an acute bout of exercise enhances retrospective memory (i.e., memory for previously learned information, facts, and events). However, the vast majority of this research has used aerobic exercise, and few studies have examined the effects of acute bouts of resistance exercise (strength training). Moreover, researchers have yet to examine the effects of either aerobic or resistance exercise on prospective memory (i.e., the ability to remember to execute tasks in the future). Thus, the purpose of the present study was to examine the effects of acute bouts of aerobic and resistance exercise on prospective and retrospective memory. A between-groups experimental design was used in which 120 students were randomly assigned to watch viral videos for 30 min while performing moderate-intensity aerobic exercise, resistance exercise, or sitting (control). Three prospective memory tests and two retrospective memory tests were assigned before the exercise phase. Participants were instructed to execute one prospective memory test during the exercise phase and to execute the remaining prospective and retrospective memory tests after the exercise phase. Relative to aerobic exercise, sitting enhanced prospective memory performance during the exercise phase. In contrast, relative to sitting and aerobic exercise, resistance exercise enhanced performance on one of the prospective memory tests that required execution after the exercise phase. These results indicate that prospective memory is diminished during acute bouts of aerobic exercise (likely due to distraction) but is enhanced shortly after resistance exercise. Thus, resistance exercise may represent a viable strategy for improving prospective memory.

Step-Count Accuracy of Physical Activity Monitors During Pregnancy in Free-Living Conditions: 2901 Board #8 June 2 1

Previous studies have assessed the validity and reliability of physical activity monitors worn by pregnant women under laboratory conditions. However, physical activity monitors have not been assessed under free-living conditions in pregnant women. PURPOSE: 1) Determine the step-count accuracy of four commercially-available physical activity monitors worn by pregnant women under free-living conditions and 2) examine the effect of pregnancy trimester on monitor accuracy. METHODS: Participants were pregnant women (n=28) in their second or third trimesters who were 18-40 years of age and free of contraindications to exercise during pregnancy. Participants wore three consumer-grade activity monitors (FB, OM, NL) and two research-grade activity monitors (AG, SW) for three days of free-living activity during all waking hours. Steps recorded over the three days for the FB, OM, NL, and AG were compared to SW recorded steps (the criterion measure) in order to calculate percentage of actual steps taken ([measured steps / actual steps] x 100). Paired-samples t-tests were performed to determine differences in accuracy between monitors and one-way ANOVAs were utilized to determine whether pregnancy trimester affected monitor accuracy. RESULTS: The analytical sample consisted of 18 women in their second trimester and 10 women in their third trimester with an overall mean gestational age of 23.9 ± 8.19 weeks and a mean daily step-count of 9354.3 ± 3363.9 steps (as determined by SW). Steps taken per day did not significantly differ between second and third trimester women (F(1, 26)=0.69, p=0.42). The FB and NL were most accurate with mean percentage of actual steps taken recorded at 69.9% and 69.5% respectively. The AG (t(27)=3.13, p<0.01) and OM (t(27)=-6.27, p<0.001) performed significantly worse with 62.7% and 52.1% of actual steps. Trimester did not significantly affect monitor accuracy. CONCLUSION: Compared to the criterion, all other monitors underestimated actual steps taken, with the FB and NL demonstrating smaller underestimations than the AG and OM in a free-living environment. Accuracy of these monitors appears to be worse during pregnancy free-living conditions compared to results of studies performed in controlled laboratory conditions.

Validation of Accelerometer-Based Energy Expenditure Prediction Models in Structured and Simulated Free-Living Settings

ABSTRACT This study compared accuracy of energy expenditure (EE) prediction models from accelerometer data collected in structured and simulated free-living settings. Twenty-four adults (mean age 45.8 years, 50% female) performed two sessions of 11 to 21 activities, wearing four ActiGraph GT9X Link activity monitors (right hip, ankle, both wrists) and a metabolic analyzer (EE criterion). Visit 1 (V1) involved structured, 5-min activities dictated by researchers; Visit 2 (V2) allowed participants activity choice and duration (simulated free-living). EE prediction models were developed incorporating data from one setting (V1/V2; V2/V2) or both settings (V1V2/V2). The V1V2/V2 method had the lowest root mean square error (RMSE) for EE prediction (1.04–1.23 vs. 1.10–1.34 METs for V1/V2, V2/V2), and the ankle-worn accelerometer had the lowest RMSE of all accelerometers (1.04–1.18 vs. 1.17–1.34 METs for other placements). The ankle-worn accelerometer and associated EE prediction models developed using data from both structured and simulated free-living settings should be considered for optimal EE prediction accuracy.

Associations Among Work-Related and Leisure-Time Physical Activity With Level of Nausea During Pregnancy

Objective: Pregnancy-induced nausea and vomiting are common maladies during early pregnancy and may be related to physical activity (PA). Our objective was to determine relations among work-related PA (work PA), leisure-time physical activity (LTPA), and nausea during the first trimester. Study design: Online or mailed surveys with questions on pregnancy-related nausea, work PA, and LTPA were completed by 70 women at 15 to 30 months postpartum. Women recalled nausea during the first trimester (none, ≤1 h/d, 2-3 h/d, 4-6 h/d, ≥6 h/d) as well as LTPA frequency, duration, and type. Women also recalled total working hours in their first trimester and percentage of time sitting, standing, and walking at work. Results: A total of 42 women (60%) were categorized as having high nausea (≥2 h/d). Mann-Whitney U tests showed that women with low nausea had significantly more MET minutes per week of LTPA (P = .05) and hours per week spent standing at work (P = .03). Logistic regression analyses showed standing for ≥20 h/wk at work was related to reduced odds of high nausea (adjusted odds ratio = 0.23; 95% CI = 0.06-0.96), whereas meeting LTPA guidelines was nonsignificantly related to reduced odds. Conclusion: These findings suggest an inverse relationship between first trimester PA and level of nausea. Further investigation is needed to determine the directionality of these relations.