title: The pregnant "waddle": an evaluation of torso kinematics in pregnancy.
abstract: Although pregnant women are anecdotally said to "waddle" during gait, researchers have not quantified the kinematics of these gait alterations. The purpose of this study was to examine the effects of pregnancy on thoracic and pelvic kinematics during gait.
  
  
  METHODS
  Data were collected on 29 pregnant subjects in the mid-second and third trimesters and on 40 control women. Three-dimensional kinematic data were collected on subjects walking at their freely-chosen speed. Right foot heel-strike (RHS) and left foot toe-off (LTO) were determined from force plate data. Thoracic and pelvic angles at RHS, step width, mediolateral translation of the C7 and L4 vertebrae, and the ranges of motion (ROMs) of the thorax and pelvis over the gait stride were determined. A series of MANCOVAs were performed with trimester (second, third, and control) as the independent variable and velocity as the covariate (α=0.05). Post-hoc analyses were performed when appropriate.
  
  
  RESULTS
  Increased lateral translation of the C7 and L4 vertebrae (third trimester>second trimester>control, p<0.05) was noted, accompanied by an increased step width in the third trimester (p=0.03). At heel strike, pregnant women had greater thoracic extension (third trimester>second trimester>control, p<0.05) and greater anterior pelvic tilt (third trimester>control; p<0.05). Sagittal plane thoracic ROM was less in the third trimester compared to controls (p<0.01).
  
  
  CONCLUSIONS
  Pregnant women demonstrated a lateral shifting of the body during gait, which accompanied a greater step width. The increased thoracic extension and anterior pelvic tilt, along with decreased sagittal plane ROM are likely adaptations to increased abdominal size.
authors.affiliation: Division of Exercise Physiology, Department of Human Performance and Applied Exercise Science, West Virginia University, Morgantown, WV, USA; Department of Health and Physical Activity, University of Pittsburgh, Pittsburgh, PA, USA. Electronic address: jlmccrory@hsc.wvu.edu.
authors.forename: Jean L
authors.initials: JL
authors.lastname: McCrory
authors.affiliation: Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: April J
authors.initials: AJ
authors.lastname: Chambers
authors.affiliation: West Penn Allegheny Health System, Pittsburgh, PA, USA.
authors.forename: Ashi
authors.initials: A
authors.lastname: Daftary
authors.affiliation: Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: Mark S
authors.initials: MS
authors.lastname: Redfern
mesh_terms: D000222:Adaptation, Physiological; D000328:Adult; D001696:Biomechanical Phenomena; D002574:Cervical Vertebrae / Q000502:physiology; D005260:Female; D005684:Gait / Q000502:physiology*; D006801:Humans; D008159:Lumbar Vertebrae; D010388:Pelvis / Q000502:physiology*; D011247:Pregnancy / Q000502:physiology*; D011262:Pregnancy Trimester, Second; D011263:Pregnancy Trimester, Third; D016059:Range of Motion, Articular; D013909:Thorax / Q000502:physiology*; D060726:Torso / Q000502:physiology*; D016138:Walking / Q000502:physiology; D055815:Young Adult
keywords: Gait; Kinematics; Pregnancy; Range of motion; Trimester; Walking