Normal Walking: An Overview Based on Gait Analysis.

Gage J, Hagen BT, Phelps J, Stout J. St Paul, MN 55101, Motion Analysis Laboratory, Gillette Children's Hospital. 1993, VHS, 35 min, $130.

The stated purpose of this videotape is to introduce the mechanisms of normal walking and gait analysis to those who treat people with disabilities. The videotape effectively uses human subjects, a computer-simulated walking skeleton with attached muscles, and an array of graphs and diagrams to provide an overview of the variables commonly studied in gait analysis. Freeze-frames, split screens, and slow-motion video techniques enhance the presentation.

The videotape begins with an introduction to "The 5 Attributes of Gait," namely, stability in stance, foot clearance in swing, prepositioning of foot for initial contact, adequate step length, and energy conservation. A brief overview of the developmental aspects of gait is presented. The videotape then provides a clear set of definitions and illustrations for terminology commonly used in gait analysis. The terminology developed by the Gait Laboratory at Rancho Los Amigos Medical Center, Downey, Calif, for subdivisions the gait cycle is used.

The videotape presents an excellent background for viewers to help them understand the mechanical aspects of laboratory gait analysis. Examples of graphs illustrating mechanical variables during a gait cycle are provided and thoroughly explained. There is a thorough, yet concise, description of inverse dynamics, internal and external joint moments, and joint power during walking. Concentric and eccentric muscle contractions are defined and illustrated using the simulated model, with the muscles illuminated in different colors depending on the type of contraction.

The videotape then provides an overview of the primary kinematic and kinetic parameters at the ankle, knee, and hip in the sagittal plane during a typical gait cycle. Graphs illustrating the joint angular position, moments, and power are provided and explained. Muscle activity is illustrated using the simulated model. A vector that is superimposed on the model illustrates the relationship between the lower-extremity joints and the ground reaction force. The series of human and simulated models are effective tools that enhance the viewer's understanding and integration of the kinetic and kinematic variables, A similar analysis of coronal- and transverse-plane motion is described briefly.

In its stated conclusion, the videotape addresses selected clinical situations that compromise the "Attributes of Gait." The videotape continues with a brief coverage of energy conservation including mechanisms of energy conservation, clinical examples of inefficient energy use, and a listing of methods to measure energy costs. This section on energy conservation seems misplaced in the conclusion portion of the videotape. The clinical examples in this section are covered somewhat superficially and seem beyond the scope of the videotape's purpose.

Overall, the videotape provides a clear and concise overview of the primary kinetic and kinematic variables studied in gait analysis. Although the general content appears to be accurate, there is no accompanying text or references. Because of its excellent integration, description, and illustration of kinematic and kinetic gait variables, I would highly recommend this videotape as an adjunct tool for the instruction of physical therapists and physicians.