Pregnancy Walking Cadence Does Not Vary By Trimester

Abstract

PURPOSE: Walking is the most commonly reported mode of physical activity among the general population and also among pregnant women. Pregnancy-related changes in walking speed, gait dynamics, and total physical activity have been reported in past research, but free-living step cadences and their rates of change across pregnancy have not been studied. The purpose of this study was to describe free-living stepping cadence in pregnant women and examine differences between second and third trimester women. METHODS: Fifty pregnant women were recruited for this study and n=45 was the analytic sample size; 46.7% were in their second trimester (13-25 weeks) while 53.3% were third trimester (≥26 weeks). Participants completed a survey of demographic characteristics and wore an accelerometer on their non-dominant wrist for 7-8 days; they were instructed to wear the device as much as possible during waking hours. These accelerometer data were downloaded in 60-sec epochs, allowing for determination of min-by-min walking cadence, defined as steps/min. Mean steps/day, mean cadence, median cadence, maximum cadence, peak cadence (average cadence over the 30 minutes of highest cadence in each day), mean time spent in moderate- to vigorous-intensity physical activity (MVPA, time spent with cadence ≥100 steps/min), and mean daily time spent in several cadence ranges (0-9, 10-19, 20-29, 30-39, 40-49, 50-59, 60-69, 70-79, 80-89, 90-99, 100-109. 110-119, 120-129, 130-139, 140-149, 150-159, 160-169, <50, <100, ≥100, and ≥130 steps/min) were calculated for each participant. Between-trimester differences were determined using independent-samples t-tests. RESULTS: Average daily steps were 11,060.1±2,955.3; 66.7% of second trimester and 54.2% of third trimester women met daily step recommendations of 10,000 steps/day, but 0.0% of the sample accumulated the recommended 150 min/wk of MVPA. There were no differences by trimester for cadence at any step rate. CONCLUSIONS: Overall, pregnant women accumulated high numbers of steps per day but at low cadences; neither daily steps nor cadence varied from second to third trimester. These data suggest that steps and MVPA recommendations are not equivalent and therefore should not be used interchangeably, especially during pregnancy.