Lower Limb Differences and the Center of Pressure Control Test with Visual Feedback for Junior Soccer Players

Haruka Kawabata,Takaaki Miyake,Yutaro Kudo,Izumi Yoshi

doi:10.11648/j.ajss.20210901.14

Abstract

This study aimed to compare the COP (center of foot pressure) control ability of junior soccer players between the kicking foot and the supporting foot using the COP control test. The participants were 40 junior soccer players (133.6±5.4 cm, 28.8±3.4 kg, 9.1±0.6 years old, soccer history: 3.8±1.3 years) belonging to a local soccer team. The COP control test was carried out using the COP trajectory measuring instrument T.K.K5810 and COP adjustment software 1.1.0 (Takei Scientific Instruments Co., Ltd.) to examine the lower right and left lower limb differences in the COP control ability. Of the 40 participants, 35 who kicked the ball with their right foot according to the questionnaire took part in the COP control test. The target-tracking COP control test tracks the target that moves regularly on the monitor with the COP and measures the total error over time. Each participant randomly practiced one standing position on both feet and one standing position (kicking foot and supporting foot), took a 30-second break between trials, and then performed two trials. The evaluation variable was total COP errors made in 30 s with the moving target. Of the two trials, for each player, the data with the best record were included for analysis. The mean COP control test scores when standing on one leg were 602.8±163.2 cm for the kicking leg and 561.6±159.1 cm for the supporting leg. The COP control test score with both feet standing was 487.0±146.2 cm. The scores of one-foot standing (kicking foot and supporting foot) were significantly higher than those for participants standing on both feet (p < 0.05), and many participants had better scores for their supporting foot than their kicking foot. However, there was no significant difference in the mean value of the kicking foot and the supporting foot and of the symmetry index, the effect size was also small. The results indicate that the COP control ability of junior soccer players does not differ between their kicking foot and their supporting foot.

Highlights

Human limbs appear to be symmetrical, but they have lateral functionality, exemplified by our ability to stand on one foot, footfall patterns in walking, and the ease with which we can stand on one leg or kick one foot while standing on the ground
The purpose of this study was to use the COP control test to examine the laterality of lower limbs in junior soccer players while maintaining the standing posture
No significant left-right difference was found in the mean value and symmetry index (SI), and the effect size showing the magnitude of the mean value was small

Summary

Introduction

Human limbs appear to be symmetrical, but they have lateral functionality, exemplified by our ability to stand on one foot, footfall patterns in walking, and the ease with which we can stand on one leg or kick one foot while standing on the ground. There are individual differences in functional laterality. We used the body tracking test developed by Yoshida et al [1,2] as a reference to develop a COP (Center of foot pressure) control test. Thereafter, we tested the test’s reliability, sex differences, and the effects of aging on body balance control. We sought to compare the results of the body balance control test and dynamic balance test [3, 4]

Objectives

Methods

Results

Discussion

Conclusion