Kinematics and kinetics of gait: from lab to clinic.

Dynamic gait evaluation allows examination of the intrinsic and extrinsic factors affecting an individual's ability to walk or run. This article identifies the gait cycle so that common terminology can be used to discuss and compare walking and running. The range of motion, or kinematics, used during gait can be seen subjectively in the hallway of the clinic but can be further objectified in a motion analysis laboratory. Kinetics, or the forces that cause the body to move, are collected in a laboratory environment. Understanding the internal and external forces acting on the body, the mobility they produce at the joints, and the corresponding effect on biomechanics helps identify sources of dysfunction. A discussion on economy highlights factors affecting the ability to move with a given amount of energy cost.