•  
  •  
 

WALKING WITH ADDED MASS POTENTIALLY INCREASED CENTER OF MASS VERTICAL DISPLACEMENT IN NON-PREGNANT WOMEN

Abstract

Pregnant women walk with added mass distributed anteriorly around their pelvis. This added mass, which can range between 15-35 lbs for singleton pregnancies, shifts their center of mass (CoM) forward and can affect walking biomechanics. While previous studies have assessed musculoskeletal adaptations in response to hormonal variation during pregnancy, less is known about the adaptations in walking kinetics due to added mass. PURPOSE: This study aimed to assess how walking kinetics and CoM vertical displacement changes in response to added mass in non-pregnant women. METHODS: Five non-pregnant women walked under 4 conditions: without added mass and with added mass of 10, 20, and 30 lbs to simulate pregnancy weight gain. Sixty percent of the added mass was distributed anteriorly to the pelvis, while 40% was distributed in posteriorly. Participants walked at their preferred speed, with two speed gates ensuring speed variation within 10%. We recorded ground reaction forces in the vertical direction (vGRF) and calculated the first (Fz1) and the second peaks (Fz2) of vGRF, and vertical loading rates (VLR). Force data were normalized to the participants’ total body weight (BW), including the added mass for each condition. We used double integration method to obtain CoM vertical displacement within a gait cycle, and calculated the CoM vertical displacement during the first double stance phase (CoMzinitial) and the total CoM vertical displacement during a gait cycle (CoMztotal). Linear mixed-effect models were used to assess the effect of added mass on all variables. RESULTS: The added mass used in this study simulated a weight gain ranged between 7.3% to 21.8% on average. Fz1, Fz2, and VLR changes were proportional to the added mass and remained unchanged when normalized by BW (p = 0.71-0.95). Linear mixed effect model showed that for every 1% increase in BW, CoMztotal increased by 0.28% (p = 0.036), and CoMzinitial increased by 2.8% (p < 0.001). CONCLUSION: We found that added mass increased CoM vertical displacement during the first double-stance phase in non-pregnant women. The effect of added mass combined with the effect of hormonal changes should both be taken into consideration when analyzing walking biomechanics in pregnant women.

This document is currently not available here.

Share

COinS