New Balance is a facility where orthotic devices are designed to relieve pressure from feet and legs. Team member Brett visited with his parents and thought this might be a way to conduct formal force tests of the materials. The use of a force plate machine and a computer produces a visual image while calculating the ground reaction force in newtons. A person stands on a force plate that looks similar to a bathroom scale. A computer then measures the pressure points on the feet using a color-coded visualization. The device used was called a Tekscan. The pressure measurement device provides accurate, reliable quantitative data to accompany qualitative data and observations about ground reaction force. The Tekscan system includes innovative scanning electronics, application specific sensors, and WindowsTM-based software designed for data analysis.
In two gallon Ziploc bags, 4 liters of each type of surface material for a trail was placed – sand, gravel, fly ash, and caliche. The New Balance owner allowed us to bring in samples of the materials being considered for the trail surface. Each material in the Ziploc bag was put on the machine. Next, a team member stood on the bag and the pressure from the surface was measured and displayed through a computer and display. For each material, a display was shown which represented the force of the surface on the human foot. The greater the force, the harder the surface would be on the human body and the least likely it should be chosen as the surface for the trail. Photographs were taken of the images and a color-coded grid corresponded to force in newtons being applied. Red represented much force and blue represented little or no force, depending on the shade of the color. Formal testing using biomechanics allowed exact measurements of ground reaction force (GRF). |