Ground reaction forces during gait in pregnant fallers and non-fallers

Pregnant women are at a high risk of experiencing a fall. To our knowledge, ground reaction forces (GRFs) in pregnant fallers and non-fallers have not been reported. Purpose: The purpose of this study was to examine the effects of pregnancy and fall history on GRFs during walking. Methods: Forty one pregnant subjects in the mid 2nd and 3rd trimesters (pregnant fallers: n = 15, pregnant non-fallers: n = 14), and 40 control women walked at a freely chosen walking speed along an 8 m walkway. A force plate, hidden in the walkway, was used to collect GRFs (1080 Hz). Kinematic data (120 Hz) were collected from a marker placed on the lumbar spine to estimate walking velocity. GRF variables included mediolateral Center of Pressure (COP) excursion, and GRFs normalized to body mass. A two factor ANOVA (trimester x fall group) was used to compare subject demographics, and walking velocity (alpha = 0.05). A two factor ANCOVA (trimester x fall group, covariate: velocity) was performed to examine other GRF variables (Bonferroni corrected alpha = 0.006) and the mediolateral COP excursion (alpha = 0.05). Results: Walking velocity was greater in the control group (p < 0.05). No differences were seen in the GRFs or COP movement between trimesters or between pregnant fallers and non-fallers. Conclusions: When walking velocity was considered in the statistical model, ground reaction forces are essentially unchanged by pregnancy. (C) 2011 Elsevier B.V. All rights reserved.