Analysis of the Influence of Age Stages on Static Plantar Pressure Indicators for Karate Do Practitioners (Preliminary Report)

Abstract

The investigation aims at static examination and determination of differences for three age groups: under 13, 13–15 years old and over 15, all practitioners of the martial art karate do. This investigation occured at the level of the main parameters, measured using the FreeMed baropodometric platform and Free Step software by Sensor Medica: plantar surface areas, location of the pressure center (C) inside the support polygon, imbalances noticed at the level of the plantar areas, Pmax value, weight distribution on each foot and at the level of the rearfoot and forefoot areas, misalignments of the pressure centers of each foot, etc. Results: subjects under the age of 13 had the highest number of cases related to the off-centered positioning of the pressure center (C); the groups of those under 13 and over 15 years old located in most cases Pmax at the level of the left retropodal part, and those between 13–15 years old have a location on the dominant leg, at the level of the right retropodal part. The highest numbers of cases of normal bilateral leg are for the group under 13 years, and the other groups have a higher incidence of various plantar imbalances. The analysis of variance (F) identified only two situations in which the independent variable, “age stages,” significantly influences the resulting parameters, at the level of the non-dominant foot: forefoot_left_surface and total_left_surface. The data differences for the right/left pairs within each batch generate insignificant values of |Z| for most cases, with the superiority of the dominant foot parameters for the first two age groups, but in the case of the group over 15 years old, some results are atypical, with higher average values of left/non-dominant foot parameters in the following cases: total_left_Pmax, total_left_Pavg, rearfoot_left_load_percent, rearfoot_left_weight_ratio_percent. The comparison between the data pairs for all three batches (between the forefoot and rearfoot plantar areas) generated significant values of |Z| only for the area of the plantar surfaces. The older the subjects, the more obvious the plantar load on the forefoot area, which is similar to the results of some martial arts studies analyzed here, and is determined by the long use of the non-dominant foot as a support base, during kicks with the dominant one.