A 3D mathematical model to predict spinal joint forces for a child with spina bifida

Children with spina bifida (SB) can exhibit excessive arm swing, trunk sway, and pelvic tilt during walking. To understand the relationship between abnormal low back forces (LBF) and gait disorders in SB, we derived a mathematical model for evaluating LBF in this population. One unimpaired child and a child with SB were tested. A 3D motion analysis system and force plate were used to collect kinematic and ground reaction force data during walking. A mathematical model created using MATLAB software was used to calculate LBF for each child. The LBF for the child with SB was three times greater in the medio-lateral direction than for the unimpaired child. In the anterior-posterior direction, the LBF for the child with SB acted mostly towards the anterior trunk. In addition, the LBF of the child with SB increased by 24.5% of body weight at the fastest walking speed. (C) 2009 Elsevier B.V. All rights reserved.