Department of Kinesiology, Samford University, 800 Lakeshore Dr. Birmingham AL, USA.
Department of Integrative Physiology and Health Science, Alma College, 614 W Superior St. Alma MI, USA.
Gait Posture. 2020 Jun;79:234-238. doi: 10.1016/j.gaitpost.2020.05.012. Epub 2020 May 14.
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.
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?
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.
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.
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.
孕期身体活动有诸多益处，但很少有孕妇能达到美国身体活动指南的要求。传统上，身体活动的测量是通过中等强度和/或剧烈强度活动的时间来衡量的，但量化强度具有挑战性。目前，人们越来越关注测量日常步数和步频（或步伐率），以作为整体身体活动和活动强度的指标。
当通过佩戴在髋部的 ActiGraph（ActiGraph 公司，彭萨科拉，佛罗里达州）加速度计收集数据时，孕妇的自由步行步频是否会在整个孕期（从 20 周到 32 周）和产后（产后 12 周）发生变化？
共有 32 名孕妇参加了一项孕期身体活动的纵向研究；这些孕妇在 20 周妊娠时、32 周妊娠时和产后 12 周时，将加速度计佩戴在右侧髋部一周。数据用于确定每日总步数、不同步频范围内的时间（分钟/天）、大于 100 步/分钟和大于 130 步/分钟的时间分钟数以及平均步频、中位数、最大步频和峰值步频。
与第二孕期（每天少 1164 步）或产后（每天少 1397 步）相比，孕妇在第三孕期每天的步数明显减少。与仅第二孕期相比，第三孕期的孕妇每天进行中高强度身体活动的时间（步频≥100 步/分钟）明显减少（少 4.1 分钟/天），且峰值步频明显降低（少 10.6 步/分钟）。
这些数据表明，与第二孕期和产后相比，孕妇在第三孕期的步幅减少，步频较慢，这表明孕期的总身体活动以及绝对活动强度都发生了变化。
