Effect of age and gender on the main baropodometric parameters: Normative data for pressure plates

Introduction: Foot morphology and biomechanics are affected by age and gender. As far as the age is concerned, this is consequence of biological alterations of joints and soft tissues which can also be detected by modifications in plantar pressure measurements. While the relationship between some pedobarographic-based parameters and different foot types has been reported in a study involving a large population [1], our current understanding of how ageing affects plantar pressure during walking is still limited. Aim of the study was to characterize plantar pressure data during walking according to gender and age in a population of healthy subjects. The pedobarographic-based foot parameters are expected to provide useful information for genderand age-specific populations. Methods: From January to July 2016 more than three hundred subjects were visited by an experienced podiatrist at the Movement Analysis Laboratory of Istituto Ortopedico Rizzoli, and also in other locations: a primary school; a gymnastic training center; a volleyball training center, and aswimmingpool. 133 subjects (70 M, 63 F) with BMI < 29 presenting asymptomatic feet with normal heel alignment (heel varus < 5 deg) and medial longitudinal arch, and with no previous history of lower limb trauma or surgery, were acquired using a 2304-sensor pressure plate (P-walk, BTS, Italy). Five left and five right steps were recorded for each subject while walking at comfortable speed. A custom software was developed and used to determine pedobarographic-based parameters from plantar pressure data [2]: arch-index (AI, %); centre of pressure excursion index (CPEI, %); peak pressure (PP, kPa); pressure-time integral (PTI, kPa*s); foot progression angle (FPA, deg); foot length and foot width (mm). Subjects’ data were pooled according to gender, and in four age groups: 6–12; 13–20; 21–40; and 41–60 years. For each gender, differences in pedobarographic parameters between age groups were determined via Kruskall–Wallis test with significance at 0.05. Mann–Whitney test was used to determine differences in each parameter between age-matched gender groups. Results: Differences were found in all parameters across age groups, with the exception of AI and CPEI. The 5–12 years group showed the smallest PP, PTI and foot dimensions for both genders. In general, FPA increased with age: the oldest group showed larger FPA than the youngest group (Fig. 1). With exception of the youngest group, foot dimensions were always larger in males. Differences between males and females in several parameters were found in the 13–20 years group. For example, median PTI in the left foot was 111 kPa*s [94–132] in the female group and 142 kPa*s [119–171] in the male group (p = 0.009). Discussion: Pressure plates are useful and reasonably priced instrumentation for the analysis of plantar pressure. While this instrumentation is increasingly used by podiatrists, plantar pressure data are often assessed on a qualitative basis only. According to this study, several pedobarographic-based parameters characterizing foot biomechanics during walking are age- and gender-dependent. Gender- and age-specific normative data are thus recommended when assessing foot biomechanics and in the diagnosis of foot ailments. This data may help assist with the diagnosis of foot pathologies and morphological alterations, and with the interpretation of foot biomechanics in healthy subjects. References [1] Menz HB, et al. Rheumatology 2013;52:2275–82. [2] Caravaggi P, et al. Bone Joint J. Orthop. Proc. Suppl 2017;2:19.