Variability of plantar pressure data. A comparison of the two-step and midgait methods.

The number of trials required to obtain a reliable representation of the plantar pressure pattern is an important factor in the assessment of people with insensate feet or the use of plantar pressure data as a basis for fabrication of foot orthoses. Traditionally, the midgait method has been used for the collection of pressure data, but the large number of walking trials required by this method can increase the risk of injury to the plantar surface of the insensate foot. As a result, the two-step method of plantar pressure data collection has been advocated. The purpose of this investigation was to determine the degree of variability in regional plantar pressure measurements using the midgait and two-step methods of data collection. Plantar pressure data were collected from ten volunteers (five men and five women) between the ages of 20 and 35 years in 20 trials using both data-collection protocols. The results of the study indicate that three to five walking trials are needed to obtain reliable regional peak pressure and pressure-time integral values when the two-step data-collection protocol is used. Although either method can be used for pressure data collection, one method should be used consistently when repeated assessments are required.