Comparison of Muscle Activities of the Posterior Oblique Sling Muscles among Three Prone Hip Extension Exercises with and without Contraction of the Latissimus dorsi

PURPOSE: We investigated the most effective way to activate the posterior oblique sling muscles by performing prone hip extension exercises. METHODS: An electromyography system was used to measure the activation of the posterior oblique sling muscles (latissimus dorsi, gluteus maximus, multifidus, and biceps femoris) in three different prone hip extension exercises of in 12 healthy individuals (6 men and 6 women): 1) prone hip extension, 2) prone hip extension with internal rotation and extension of the arm, and 3) prone hip extension with internal rotation and extension of the arm with a 1-Ib dumbbell. RESULTS: The overall muscular activation of the posterior oblique sling muscles was more increased when performing 1) prone hip extension with internal rotation and 2) prone hip extension with internal rotation and extension of the arm with a 1-Ib dumbbell as compared with that during prone hip extension except for the biceps femoris activation. There was a statistically significant difference in the activities of the contralateral multifidi among all three exercises; of the ipsilateral multifidi in PHE1) prone hip extension alone, PHE2) prone hip extension with internal rotation and extension of the arm and PHE3) prone hip extension with internal rotation and extension of the arm with 1-Ib dumbbell; and of the ipsilateral gluteus maximus among all the prone hip extension exercises. There was no significant difference in the activity of the biceps femoris among the three exercises. CONCLUSION: Prone hip extension with internal rotation and with internal rotation and extension of the arm with 1-Ib dumbbell can activate the posterior oblique sling muscles and so prevent back pain in healthy people.