Investigating Efficiency and Stability of Gait Using a Two Triaxial IMU Sensor System

Abstract

This work aimed to develop a simple, two-sensor system to measure gait efficiency and stability. The system was tested by measuring the compromised gait pattern of 15 healthy adults (aged 18-30). The gait pattern was altered by forcing participants to walk on their toes on their right side using an ankle-foot orthotic (AFO) and heel wedges. There were 5 conditions: a control condition, a zero AFO condition (AFO with no restrictions or wedges), and a low (5 degrees of plantar flexion), medium (15 degrees of plantar flexion) and high (25 degrees of plantar flexion) wedge conditions. Participants were instrumented with two-sensors, one on their low back, and the other attached to their head, as well as motion tracking markers placed on landmarks of the lower limbs and a motion tracking marker on each sensor. Participants completed ten, 7-meter, walking trials under each condition. Four outcome variables were calculated, two for efficiency and two for stability. The outcome variables were calculated from the movements of the low back and the head and the relationship between them. Repeated measures MANOVAs (Multivariate Analysis of Variance) found an overall decrease in gait efficiency and stability with increasing plantar flexion angle. There was no significant interaction between measurement tool and condition, suggesting that the sensors measured changes in the outcome variables that were similar to those measured by the motion capture system. This work is the first step in the validation of a simple two-sensor system to measure efficiency and stability of gait. Efficiency and stability are two objective and clinically relevant variables that when combined with the tests presently used in clinic will give a more holistic view of an individual’s gait.