Effect of feedback corrective exercise on knee valgus and electromyographic activity of lower limb muscles in single leg squat

The aim of this study was assessing the effect of feedback correcting exercise in front of mirror during running on frontal plane knee and pelvic kinematic and electromyography activity of some lower extremity muscles in single leg squat (SLS). This study was quasi experimental. 23 active female subjects participated in two experimental and control groups with mean age (21.86± 2.43) years. experimental group contains subjects with knee valgus and pelvic drop angle more than a mean plus one standard deviation of the population in functional SLS. Muscular activity (RMS) of gluteus maximus, Gluteus medius, rectus femoris, vastus medialis, vastus lateralis, biceps femoris and semitendinosus, angle of knee valgus and pelvic drop were register in end of SLS Pre and post of 8 training sessions. Comparing Variable has done with independent t statistical test between 2 groups and pair sample t test within each groups with significant level of 0.05. Statistical analysis Before training showed no significant differences in pelvic drop between two groups (p≥0.05), but knee valgus angle was significantly more than control group (p≤0.05). In spit that most muscle activities (% MVC) except biceps femoris (p≤0.05), were greater in experimental group, no significant difference (p≥0.05) has seen in two groups. Comparing pre and post test has showed no significant difference in knee valgus of experimental group, however it decreased around 2 degrees and although %MVC decreased in all muscles, just rectuse femoris has shown significant difference (p≤0.05). No significant difference has seen in control group in all variables (p≥0.05). Results Findings showed poor neuromuscular control in experimental group which improved to some extent after training because lower muscle activity and energy consumption in specific movement with similar kinematic indicate improvement of motor control or cause learning. It seems mirror corrective exercise is responsible of learning by activating mirror neurons. Also decreasing muscular activity in movements cause decreasing fatigue, so possibility of injury may decrease, regarding the relation between fatigue and most injuries. Although there is some evidence that this training may cause positive changes in knee valgus and lower limb neuromuscular activity but more researches are needed to reach certain results.