ABSTRACT
PURPOSE: This paper proposes proper and effective neck exercises by comparing the deep and superficial cervical flexor muscle activities and thickness according to the pressure level during cranio-cervical flexion exercises between a normal posture group and forward head posture group. METHODS: A total of 20 subjects (8 males and 12 females) without neck pain and disabilities were selected. The subjects' craniovertebral angles were measured; they were divided into a normal posture and a forward head posture group. During cranio-cervical flexion exercises, the thickness of the deep cervical flexor neck muscle and the activity of the surface neck muscles were measured using ultrasound and EMG. RESULTS: The results showed that the thickening of the deep cervical flexor was increased significantly to 28 and 30 mmHg in the forward head posture group. The sternocleidomastoid muscle activity increased significantly to 24, 26, 28, and 30 mmHg in the forward head posture group. The anterior scalene muscle activity increased significantly to 26, 28, and 30mmHg in the forward head posture group. A significant difference of 26, 28, and 30 mmHg in the sternocleidomastoid and anterior scalene muscles was observed between two groups. CONCLUSION: To prevent a forward head posture and maintain proper cervical curve alignment, the use of the superficial cervical flexor muscles must be minimized. In addition, to perform a cranio-cervical flexion exercises to effectively activate the deep cervical flexor muscles, 28 and 30 mmHg for normal posture adults and 28 mmHg for adults with forward head postures are recommended.