Kinematic covariation in pediatric, adult and elderly subjects: Is gait control influenced by age?

BackgroundIn human walking, kinematics of lower limb segments covary. Our objective was to assess the impact of age at different speeds (slow, medium and fast) on kinematic segmental covariation in normal subjects.MethodsThirty subjects ranged into 6 age groups (“5 years”, “10 years”, “15 years”, “20 years” and “70 years”) were included. We performed a gait analysis on a treadmill at 3 predetermined speeds: 1 (slow), 3 (medium) and 5 (fast) km h− 1, except for the 5 years group who was unable to walk at 5 km h− 1. Kinematic segmental covariation was computed and represented by a 3D-loop, described by a principal component analysis (Borghese's methodology). We studied the percentage of variance of each component of the principal component analysis, knowing that the percentage of variance of the first and the second components reflected the shape of the loop, and that the percentage of variance of the third component was an index of its planarity. The effect of age was tested using a one-way analysis of variance.FindingsWhen comparing the age groups at the same speed, we found a significant difference in the percentage of variance of the first and the second components between the 5 and the 10 years at 3 km h− 1. We also noticed a difference in the percentage of variance of the third component at 5 km h− 1 between the 10 years and the 15 and 20 years groups.InterpretationWe observed that kinematic covariation remains stable throughout adulthood between 15 and 70 years old at slow, medium and fast speed. In children, a mature percentage of variance of the first and the second components is acquired from 10 years old and a mature percentage of variance of the third component from 15 years old.