Acquirement of stability and mobility in infant gait.

We examined gait development in a longitudinal and cross-sectional study in 35 infants, age range 7-70 months. We estimated walking stability from mediolateral motion of body segments and mobility from the angular displacement of joints. Motion at the shoulder, hip, knee and ankle decreased significantly over several months after the onset of walking and thereafter changed gradually. The remarkable decrease began distally. The trunk-thigh and thigh-shank angles changed significantly until 9 months after the onset of walking. These results indicate that lateral stability, which develops earlier than mobility, is the most important factor in gait development in infants. Copyright 2002 Elsevier Science B.V.