We assessed the effects of forward head posture in the sitting position on the activity of the scapular upward rotators during loaded isometric shoulder flexion in the sagittal plane.Healthy volunteers (n=21; 11 men, 10 women) with no history of pathology participated in the study. Subjects were instructed to perform isometric shoulder flexion with the right upper extremity in both the forward head posture (FHP) and neutral head posture (NHP) while sitting. Surface electromyography (EMG) was recorded from the upper trapezius, lower trapezius, and serratus anterior muscles. Dependent variables were examined by 2 (posture) × 3 (muscle) repeated measures analysis of variance. Significantly increased EMG activity in the upper trapezius and lower trapezius and significantly decreased EMG activity in the serratus anterior were found during loaded isometric shoulder flexion with FHP. Thus, FHP may contribute to work-related neck and shoulder pain during loaded shoulder flexion while sitting.These results suggest that maintaining NHP is advantageous in reducing sustained upper and lower trapezius activity and enhancing serratus anterior activity as compared with FHP during loaded shoulder flexion.
Bibliographical noteFunding Information:
I.C. received a FPI Fellowship from Fundación Séneca (Murcia). This work was supported by Fundación Séneca (Murcia) 708/CV/ 99, European Community contracts BIO4-98-0309, QLG2-99-00793, QLG3-2000-01556, and QLG3-2000-01625 (to S.M.); Funda-ción Séneca (Murcia) PB14/FS/97, CICYT PB98-0397, and EEC contract BIO4-CT96-042 (to L.P.). The supply of polyclonal chick antiquail antibody by V.Lance-Jones (Pittsburgh, PA) and of rat AA3-Mab by B. Zalc (Paris) is gratefully acknowledged.
All Science Journal Classification (ASJC) codes
- Complementary and Manual Therapy
- Physical Therapy, Sports Therapy and Rehabilitation
- Complementary and alternative medicine