COMPARISOM BETWEEN THE DIFFERENT HIP ROTATION POSITIONS ON HIP ABDUCTION EXERCISE

Abstract

Background: The Gluteus Medius (GM) muscle is strongly involved in the control of hip joint stability and is active when postural stability is challenged in the medio-lateral direction. Alterations in activation patterns of these muscles have been documented for patients suffering from low back pain, knee, and ankle injuries. Aim: The purpose of this study was to investigate the effect of different hip rotation angles on myoelectrical activity of the three parts of the GM muscle during hip abduction exercise from side lying position in normal subjects with different angles of hip flexion. Design: A (3 tests×1 group) post experimental design was used.. Setting: The study was conducted in laboratory of biomechanics , Faculty of Physical Therapy, Cairo University. Population: Thirty pain free volunteers From out clinic of Faculty of Physical Therapy, Cairo University, their age ranged from 19 to 28 years old. Methods: A single session, repeated-measures design. The activity of each GM part (anterior, middle, and posterior) was measured in 30 pain free volunteers, their age ranged from 19 to 28 years old, using surface electromyography during three rotation movements ( neutral, 30o internal, and 45o external rotation) of the hip joint with different hip flexion angles(0o,45o, and 90o) from side lying hip abduction exercise. Muscle activation was expressed relative to Maximum Voluntary Isometric Contraction (MVIC). Differences in muscle activation were investigated using one-way repeated measures ANOVA with post-hoc Bonferroni analysis. Results: At neutral and 90o hip flexion, The activations of GM and its parts during the exercises were significantly different (p 0.01). Conclusion: The highest EMG amplitude of the muscle and its parts was when the hip flexed 90o and internally rotated during abduction. The posterior part is more active than the middle and the anterior parts in a relation to MVIC. There were significant differences between the different rotation movements of the gluteus medius muscle and its parts during abduction when the hip was in 90o and neutral hip flexion. Clinical rehabilitation impact: According to the results, the most proper position for strengthening the GM muscle and its parts was from 90o hip flexion with medial hip rotation and it should be used in progression of the rehabilitation program. The movements with less amplitudes are used at the beginning of the rehabilitation program of the GM muscle and the movements of the high amplitudes are used to progress the rehabilitation