Journal of Clinical Physiotherapy Research

Abstract

Introduction: Postural control is necessary for conducting all activities and is the result of corporation of somatosensory, visual and vestibular systems. Impairment in each of these systems leads to disturbance of postural control and increases the risk of falling and injury. Fatigue is one of the common conditions that can affect postural control. The aim of this study was to elucidate different effects of Electrical Stimulation (ES) and Voluntary (Vol) quadriceps fatigues on postural control. Methods and Materials: This cross-sectional randomized order of testing study was performed at Biomechanics Laboratory of Iran University of Medical Sciences, Tehran, Iran from December 2014 to May 2015. Sixteen healthy active males (24.5±1.36 yr; height: 155.37±53.79 cm and body weight: 70.93±4.5 kg) participated. All the participants underwent two fatigue protocols: ES and VOL contractions. Each fatigue procedure contains isometric contraction with five seconds holding contraction, two seconds rest between each contraction and intensity of voluntary contraction was 20% of Maximal Voluntary Contraction (MVC). In each fatigue protocols, muscles MVC decreased to 30% in both ES and VOL protocols. MVC and postural control measured by using a digital dynamometer and a force plate that registered the Canter of Pressure (COP). Data collected before and after completion of each fatigue protocol. Monopedal postural control was recorded in eyes closed condition. Results: Results did not show significance effect of fatigue on area and mean velocity while showed significant effect on the anterior-posterior (Y-axis) and on the mediolateral direction (X-axis). Conclusion: Thirty percent loss of MVC in quadriceps muscle did not impair postural control.