Postural Control Analysis During a Standardized Kick Task in Soccer Athletes

Abstract

Introduction: Postural control is a determining factor for functional performance and motor skills during sports activities. Objective: The objective of this study was to investigate postural control during the controlled soccer ball kicking task through a biomechanical analysis system. Methods: The sample consisted of 11 professional male athletes recruited using convenience sampling, with a mean age of 22 years. The athletes performed twenty-five precision kicks at a target, with the ball in vertical motion released by means of a hand-held device synchronized with the computed biomechanical measurements. Marking of the lower limb segments involved in the kick and the ball were analyzed by accelerometry, while postural control measures were quantified by a force platform in three axes of movement. The support leg was investigated in single leg stance during all tests on the force platform. The main variables of postural control calculated by stabilographic analysis and computed during the 25 kicks were: center of pressure (COP) displacement area, velocity and frequency of COP oscillation in the anteroposterior and mediolateral directions. The mean was used for final analysis to determine the differences in the three phases: pre-kick, kick, and post-kick. Results: The results revealed significant differences (p <0.01) between the three phases, with the kick phase presenting higher values of postural COP oscillations than the other phases. The COP area and oscillation velocity were the variables with greatest sensitivity to changes in the kick phase, obtaining an effect size of d = 14 and d = 12, respectively. In clinical terms, the increase in COP values reached 557% between the pre-kick and kick phases; this difference was reduced to 241% when compared to post-kick (i.e., difference between kick and post-kick was 316%). Conclusion . These results have important implications for the perception of postural control responses during soccer ball kicks and consequently, for injury prevention when motor and sensory deficits are diagnosed in soccer players. Level of Evidence III; Study of nonconsecutive patients; without consistently applied reference ‘‘gold’’ standard.

Development of a Cost-effective Biomechanical System for the Assessment of Kinematic and Kinetic Parameters in Soccer Players During a Lower Limb Pointing Task

“…Therefore, the three-dimensional system developed in the present study captured the participants' movement during the kicking task, in different planes/axes. The calibration results showed that the sensor presented a level of oscillation (g) range varying between -1 to +3 g, con rming that this device responded adequately to the acceleration to which it was submitted [32], which is in accordance with previous studies [22,31,32,33]. Furthermore, the platform presented an adequate connectivity, linearity and hysteresis as well as a satisfactory resolution and sensitivity of curves, combined with a structural rigidity and low weight.…”

“…Contrary to previous studies [34,35], the CoP measurement error found during the distributed load test was greater than the error observed during the application of the centralised load. This could have been caused by an uneven load distribution on the plate not well transferred to the four load cells or imperfections on the plate [22,35]. Though this characteristic appears to be negative, it showed that a system designed in this manner can reduce the hysteresis effects [21].…”

“…External forces (GRF, CoP) can be measured through a force platform which provides electrical signals relative to the applied forces [20,21]. Measuring these forces simultaneously with kinematic data through combined systems can provide a time-effective and comprehensive method [21,22,23]. A study by [22], used a combined system consisting of a force platform, an accelerometer and an electromechanical device to simultaneously measure kinetic and kinematic variables during a controlled kick by comparing the signals from the three devices.…”

Heart Rate and Lower Limb Muscle Activity on Cycle Ergometer

“…All signals were collected simultaneously and analyzed using the software EMGLab V1.1 -EMG System do Brasil 23 .…”