There are significant changes in gait across the life span, but partic
ularly after the age of 70 years. This article reviews the physiology
of gait and the motor control challenges during gait. The kinematics (
motion) and the kinetics (moment and power) of normal gait of a databa
se of healthy young and older adults are compared. Older subjects gene
rate significantly lower peak ankle plantar flexor power during gait.
The clinical significance of the reduction in ankle plantar flexion po
wer is discussed.