BACKGROUND Physical activity during pregnancy has many health benefits yet few pregnant women meet US guidelines for physical activity. Traditionally, physical activity has been measured as time spent in moderate and/or vigorous intensity activity, but quantifying intensity is challenging. There is increasing interest in measuring both daily steps and stepping rate, or cadence, as an indicator of physical activity overall and intensity of that activity. RESEARCH QUESTION Does free-living step cadence change across pregnancy (from 20 weeks to 32 weeks) and postpartum (12 weeks postpartum) when data is collected via hip-worn ActiGraph (ActiGraph Corp., Pensacola, FL) accelerometers? METHODS A total of n = 32 pregnant women were enrolled in a longitudinal study of physical activity during pregnancy; these women wore accelerometers on their right hip for one week at 20 weeks gestation, again at 32 weeks gestation, and at 12 weeks postpartum. Data were used to determine total daily steps, time spent (min/day) in various cadence ranges, minutes spent at >100 and >130 steps/min as well as mean, median, maximum, and peak cadences. RESULTS Pregnant women accumulated significantly fewer steps per day in the third trimester compared to second (1164 steps/day less) or postpartum (1397 steps/day less) time points. Third trimester women also spent significantly fewer minutes/day in MVPA (cadences ≥100 steps/minute; 4.1 min/day less) and had a significantly lower peak cadence (10.6 steps/min less), compared to second trimester only. SIGNIFICANCE These data indicate that pregnant women take fewer steps and walk at slower cadences in the third trimester compared to second and to postpartum, which indicates that total PA as well as absolute intensity of PA are altered during pregnancy.

中文翻译：

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整个怀孕和产后步行节奏的纵向变化。

背景技术怀孕期间进行体育锻炼具有许多健康益处，但是很少有孕妇符合美国体育锻炼准则。传统上，体育锻炼是根据在中等强度和/或剧烈强度运动中所花费的时间来衡量的，但是量化强度是一项挑战。人们越来越关注测量日常步伐和步伐率（或踏频），以作为总体上身体活动和活动强度的指标。研究问题当通过臀部磨损的ActiGraph（ActiGraph Corp.，Pensacola，FL）收集加速度数据时，在怀孕期间（从20周到32周）和产后（在产后12周）自由活动步调会改变吗？方法总共有32名孕妇参加了妊娠期间体育锻炼的纵向研究。这些妇女在妊娠20周时，在妊娠32周时以及产后12周时，其右髋部都使用了加速度计一周。数据用于确定总的每日步数，在各种节奏范围内花费的时间（分钟/天），在> 100和> 130步/分钟下花费的分钟以及平均，中位数，最大和峰值节奏。结果与第二个时间点（少1164个步骤/天）或产后时间（少1397个步骤/天）相比，孕妇在妊娠中期每天的步数明显减少。与仅孕中期相比，孕晚期妇女在MVPA上花费的时间/天显着更少（节奏≥100步/分钟；少4.1分钟/天），峰值步调也显着降低（少10.6步/分钟）。