EFFECTS OF PLANTAR ORTHOSIS ON DYNAMIC PLANTAR PRESSURE MEASUREMENTS IN RUNNERS

Abstract

During the past years, the use of custom-made plantar orthoses (POs) has been sharply increased among athletes. Concurrently, a great effort has been dedicated by orthotic designers and manufacturers to improve the quality of their products. Only recently, however, systems that allow dynamic plantar pressure measurements within shoes have become available. Data and information provided by these devices can potentially reveal information about both the structure and the function of the foot and may also be used to evaluate the effectiveness of specifically designed POs on plantar foot pressure. By analyzing the pressure distribution in different plantar areas and the centre of force path as well, the aim of this work was to examine the efficacy of specific custom-made POs in athletes wearing their own running shoes. For this purpose, eleven runners were randomly selected among a population of competitive athletes wearing POs. The orthosis had been made by different laboratories using different casting methods. Each subject performed two separate running trials at 12 km/h on a motorized treadmill: one trial wearing his own custom-orthotics in the shoes, and one trial without. In the two experimental conditions, data for at least six strides for each foot was collected. The Fscan inshoe pressure measurement system was used to measure piantar pressure during all trials. The system used an ultra-thin flexible and trimmable sensor with 960sensing locations distributed evenly across the entire plantar surface. These food sensors can be customized to the individual needs and sizing of each subject. According to previous studies, the results of trials with and without orthosis appeared to show a sensitivity to this change in condition. In many ofthe examined parameters, significant changes have been found between the two experimental conditions. However, in three cases, although inserts are thoughtto redistribute and decrease local plantar pressure beneath the foot, Pos significantly increased pressure in particular areas of the metatarsal region. Furthermore, in two subjects, a dramatic pressure increase had been found in the lateral portion of the midfoot suggesting an overcorrection of the medial arch support. In four subjects the effect of POs was not significant in each of the examined parameters. In only three subjects, the centre of force path was found to deviate significantly with POs.