The relationship between head posture in sitting and the performance of selected neck muscles

The purpose of this study was to examine the relationships between head posture, force production of the anterior neck muscles, and length of the posterior neck muscles. In 42 subjects, ages 18-45, force production of the longus colli, longus capitus, and rectus capitus anterior was measured, using a make test with a hand-held dynamometer. Posterior muscle length was quantified by measuring the space between the table and spine as the supine subject attempted to flatten the cervical lordosis. Photographs of head posture were evaluated by measuring the angle formed between a horizontal line through C7 and a line connecting C7 with the tragus of the ear. The only significant correlation was between anterior force production and posterior muscle length r=.327 (p=.035). Male subjects demonstrated a significant correlation between head posture and force production r=.568 (p=.034). This study hows that head posture may be related to muscle performance