Measurement of Step Widths and Step Lengths: A Comparison of Measurements Made Directly From a Grid With Those Made From a Video Recording

For those involved in the assessment of gait, there are many systems currently available that provide objective data on kinetic and kinematic gait variables. Force plates, electromyography, and electrogoniometers are just a few examples of the instrumentation that can be used by therapists to analyze gait in the clinic. Unfortunately, many of the systems used to obtain these measurements are not practical for a variety of reasons, including their complexity, high cost, time requirements, and space dependencies. Consequently, the vast majority of therapists and others involved in the day-to-day assessment and treatment of gait disorders rely on their observational skills alone. It has been demonstrated that the quality of such assessments depends upon the experience of the therapist. A number of studies have also cast doubt on the reliability and validity of these subjective assessments. Video recording has been suggested as a way of enhancing the observational skills of the clinician. Even with this extra and useful tool, videotaped observational gait analysis has been shown to be only slightly to moderately reliable when data from different observers are compared. The purpose of our study was to examine the validity and reliability of measurements of foot placements taken from a specially designed walkway grid with a color coding system, simplifying position estimation. This would be done by comparing the positions estimated from the video with those obtained by directly measuring the positions from ink marks left on the grid.

J Orthop Sports Phys Ther 2000;30(7):410–417. doi:10.2519/jospt.2000.30.7.410