Normal pressure values and repeatability of the Emed® ST4 system

The aims of this study were to assess the repeatability of the Emed® ST4 system and identify the range of pressure values observed in the normal foot. Fifty-three healthy subjects, 17 females (32%) and 36 males (68%), were recruited. Measurements were performed on two occasions approximately 12 days apart. Peak pressure (PP), contact area (CA), contact time (CT), pressure–time integral (PTI), force–time integral (FTI) and instant of peak pressure (IPP) were recorded. The coefficient of repeatability (CR) was less than 16.9% for all 122 parameters considered. The highest areas of PP were found under the second and third metatarsal heads, with mean (S.D.) equal to 361 kPa (104) and 330 kPa (84), respectively, followed by the great toe 321 kPa (141) and heel 313 kPa (77). CA was highest under the heel at 35 cm2 (5). The percentage CT was in the range 75–85% under the metatarsal heads, and 70% under the hallux. PTI was highest under metatarsal heads one to three and hallux. FTI was highest under the heel. Emed® ST4 system was found to be repeatable. The ranges of the parameters documented can be applied in orthopaedic clinics as part of the assessment of pathological conditions.