Arm coordination changes correlate with whole-body linear momentum and dynamic walking balance during pregnancy

Arm swing increases during pregnancy. Changes in arm movement may affect limb coordination and walking balance control. If excessive arm swing is needed to maintain balance or momentum during pregnancy, activities of daily living that restrict arm swing may negatively impact balance or gait propulsion by increasing fatigue or risk of falls. The purposes of this research were to examine arm coordination changes and their impact on walking balance and whole-body linear momentum (WBLM). Twenty-three pregnant women (28 ± 4 y) were tested in four-week intervals (± 2 weeks) at 18-, 22-, 26-, 30- and 34-weeks gestation. Kinematic data were measured during self-selected speed walking. Segment coordination, walking balance, and WBLM were analyzed over time. Regressions were used to analyze correlations between arm motion and the other variables. Walking balance degraded (p < 0.017) and WBLM increased (p < 0.001) from 18 weeks to 34 weeks gestation. Arm segment coordination couplings became more arm dominant over gestation (p < 0.042). These arm couplings explain 27 % of the change in WBLM during pregnancy (r = 0.521). However, only the changes in Thorax-Arm and Pelvis-Leg couplings explain some of the changes in walking balance (r < 0.326, p < 0.035). This study shows the coordination patterns the arms form with the body during pregnancy do correspond with balance, but may be more important contributors to WBLM. If arm motion is interrupted, walking energetics may degrade without the ability for compensation from other body segments due to pregnancy related strength changes.