A Validation Study of an Insole Pressure Distribution System (Pedar by Novel Inc.), 1998
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| The following research project was conducted by an undergraduate student in kinesiology. It serves as an example to illustrate the kind of small, but nevertheless important projects that students have performed in this laboratory. These projects provide a lot of hands-on experience for students, who later want to pursue advanced studies in biomechanics or therapeutic sciences. |
A Validation Study of an Insole Pressure Distribution System (Pedar by Novel Inc.), 1998 |
| Funded by: University of Minnesota UROP Program (Undergraduate Research Opportunity Program) |
| Principal Investigator : Jürgen Konczak, PhD |
| Co-Investigator: Nathan
Anderson, Undergraduate Research Assistant |
| Introduction:
The Gait and Posture Laboratory has acquired a new insole pressure system (PEDAR by Novel Inc.) to measure foot pressure during various types of locomotion. Before the system can be used in research, it is necessary to validate its digital recordings. After calibrating the system, it is essential to compare its data with another independent source. In the laboratory such an independent recording source is available in the form of a force platform (AMTI Inc.).
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Methodology:
Subjects: 8 healthy females with approximately 8 foot size (mean age 26.4 yrs.; s.d. 6.8) Apparatus: PEDAR system by Novel Inc. & AMTI force platform Procedure: Subjects performs three standing postures: quiet stance with feet together, quiet stance with only the left foot, and quiet stance with only the right foot. Measurements: Ground reaction force (N) and sway of center of pressure (mm). Analysis: Data were analyzed using a MATLAB (high-level matrix/array software |
Fig. 1: Placement of the two foot pressure insoles on the force platform. |
Fig. 2: Particpant's standing position on the insoles. |
Fig. 3: Medial-lateral positon of the Center of Foot Pressure (COFP) of one participant over a 10-second interval. Note that the two curves follow the same pattern, indicating that the PEDAR system records COFP with similar accuracy than the force platform. The offset in the two curves is due to an added constant to the PEDAR data, so that both curves would not lie on top of each other. |
Conclusion:
The results of this study show that the COFP data collected through the PEDAR system have a larger variance than the AMTI platform. We could confirm the manufacturer's claim that the PEDAR system measures force output within +- 5% of the actual force. |
| Summary Data (all trials from all 8 subjects) |
Fig. 4: Individual differences in mean ground reaction force (Z Force) between the two recording systems. |