The Effect of Three Methods of Kinesthetic Imagery, Active, and Combined Exercises on Electromyographic Pattern of Hip Hyperextension and the Muscle Strength of Gluteus Maximus and Abdominal in Women With Lumbar Hyperlordosis

Purpose: Mental exercise uses the same neuronal pathways involved in physical exercise to modify the pattern and function without stress caused by physical exercise. This study investigates the effect of kinesthetic imagery, active, and combined exercises (imagery and active) on the hip hyperextension and the power of selected lumbopelvic muscles in women suffering from lumbar hyperlordosis. Methods: In this quasi-experimental study, 36 women with lumbar hyperlordosis (age range: 30-40 years, non-athlete and without injury and surgery in the lumbar region) were selected and divided into three groups. The groups practiced three sessions per week for six weeks. We assessed the lumbar lordosis by a flexible ruler and the electromyographic (EMG) activity of the lumbopelvic muscles during hip hyperextension in the prone position by surface electromyogram. We also measured the power of the gluteus maximus using a dynamometer during hip hyperextension and the abdominal muscles using a goniometer during the double leg lowering test. All of the measurements were done before and after the intervention. The normality of the data was checked by The Shapiro-Wilk test, and the obtained data were analyzed by repeated-measures ANOVA test at the significant level of 0.05. Results: The variables of lumbar lordosis were significantly reduced in the active and combined groups in the post-test compared to the pre-test, and the strength of gluteus and abdominal muscles in the active and combined groups in the post-test significantly increased compared to the pre-test. However, the lumbar lordosis and strength of gluteus and abdominal muscles in the post-test were not significantly changed compared to the pre-test. Gluteus maximus and abdominis transverse muscle activity rates in the combined group increased significantly in the post-test compared to the pre-test, and gluteus maximus muscle activity rate in the active group increased significantly in the post-test compared to the pre-test. Gluteus maximus muscle activity in the imagery group increased significantly in the post-test compared to the pre-test. The activity of lumbar erector spinae and rectus femoris muscles decreased significantly in the active and combined groups in the post-test compared to the pre-test. However, the activity of the rectus femoris muscle decreased significantly in the image group in the post-test compared to the pre-test (P≤0.05). The results showed a significant difference between the three methods of kinesthetic imagery, active, and combined (P=0.001). There was a significant difference between the method of the imagery exercise and the active and combined exercise methods but no significant difference between methods of the active and combined exercise. Conclusion: Imagery exercises effectively modified the EMG of some lumbopelvic muscles (gluteus maximus and rectus femoris muscles). However, it had no significant effect on the strength and degree of lumbar lordosis. The combined exercise was as effective as active exercise in modifying the EMG activity of the lumbopelvic muscles and the strength of the abdominal and gluteus maximus muscles