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Perceived Exertion of Physical Activity During Pregnancy

Mallory R. Marshall and James M. Pivarnik


Maternal physical activity declines across gestation, possibly due to changing perception of physical activity intensity. Our purpose was to a) determine whether rating of perceived exertion (RPE) during a treadmill exercise changes at a given energy expenditure, and b) identify the influence of prepregnancy physical activity behavior on this relationship.


Fifty-one subjects were classified as either exercisers (N = 26) or sedentary (N = 25). Participants visited our laboratory at 20 and 32 weeks gestation and at 12 weeks postpartum. At each visit, women performed 5 minutes of moderate and vigorous treadmill exercise; speed was self-selected. Heart rate (HR), oxygen consumption (VO2), and RPE were measured during the last minute at each treadmill intensity.


At moderate intensity, postpartum VO2 was higher compared with 20- or 32-week VO2, but there was no difference for HR or RPE. For vigorous intensity, postpartum HR and VO2 were higher than at 32 weeks, but RPE was not different at any time points.


RPE does not differ by pregnancy time point at either moderate or vigorous intensity. However, relative to energy cost, physical activity was perceived to be more difficult at 32 weeks compared with other time points. Pregnant women, then, may compensate for physiological changes during gestation by decreasing walking/running speeds.

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Can Pregnancy be an Ergogenic Aid to Athletic Performance?: A Review

James M. Pivarnik, Christopher P. Connolly, Mallory R. Marshall, and Rebecca A. Schlaff

Previous research clearly indicates that exercise training decreases during pregnancy, even among the fittest of women. Despite this, women are typically able to resume their prepregnancy exercise routines soon after delivery, and in some instances, their postpartum performances are better than previously experienced. While anecdotal reports are common, there does not appear to be significant research data to explain this phenomenon. In this review, we explore possible physiologic explanations for heightened postpartum exercise performance, such as pregnancy related changes in aerobic fitness, lactate threshold, flexibility, and musculoskeletal fitness. At this time, limited data do not appear to support an ergogenic role for these variables. Another consideration is a positive change in a woman’s psyche or perceptions toward her athletic abilities as a result of her pregnancy and delivery. While this concept is theoretically possible and may have scientific merit, data are sparse. What is clear is that an increasing number of women are maintaining their physical activity and exercise routines during pregnancy, with many able to return to competition soon after delivery. Well-designed studies are needed to further explore the relationships among physiologic and psychological variables and postpartum exercise performance. Ideally, these studies should be prospective (studying women prepregnancy through the postpartum period) and include diverse samples of women with regard to activity type and fitness level.

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Step-Counting Validity of Wrist-Worn Activity Monitors During Activities With Fixed Upper Extremities

Rebekah Lynn, Rebekah Pfitzer, Rebecca R. Rogers, Christopher G. Ballmann, Tyler D. Williams, and Mallory R. Marshall

Little is known about validity of wrist-worn physical activity monitors during activities when an arm-swing is not present. The purpose of this study was to compare the step-counting validity of wrist-worn activity monitors (Fitbit Charge HR Series 2, ActiGraph GT9X Link, Apple Watch Series 4) during functional physical activities with fixed upper extremities. Tasks included treadmill walking at 3 mph and five free-living tasks (walking with a baby doll on the left hip and the right hip, holding groceries, and pushing a stroller while walking and while jogging). Device step counts were compared to hand-counted steps from GoPro video footage. Fitbit Charge had less error when compared to the left ActiGraph in both stroller walking and jogging, treadmill walking, and grocery walking tasks (p < .001 to .020). For grocery walking, walking with a baby on the right, and walking with a baby on the left, device percentage errors ranged from 0 (0.5%) to −7.6 (15.8%). For stroller jogging, stroller walking, and treadmill walking, device percentage errors ranged from −8.3 (7.3%) to −94.3 (17.9%). Tasks with the hands fixed to an item that also had contact with the floor (stroller and treadmill) had more error than when participants held an item that was not in contact with the floor (doll and groceries). Though wrist-worn, consumer-grade step-counting devices typically undercount steps in general, consumers should be aware that their devices may particularly undercount steps during activities with the hands fixed. This may be especially true with items in contact with the floor.

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Undergraduate Research in Kinesiology: Examples to Enhance Student Outcomes

James A. Carson, John K. Petrella, Vanessa Yingling, Mallory R. Marshall, Jenny O, and Jennifer J. Sherwood

Undergraduate research is emphasized as a critical component of today’s science-based undergraduate education and widely accepted as an important part of the overall undergraduate education experience. While educators agree on the value of undergraduate research, significant challenges exist related to the design of the undergraduate research experience and the faculty member’s role in it. Additional challenges include providing high-quality research experiences that benefit the education of a large number of students while maintaining feasibility and cost-effectiveness. The scope of this review is to provide an overview of research and service-learning experiences in kinesiology departments at 3 institutions of higher learning that vary in size and mission.