Effects of Artificial Forward Head and Neck Posture on Shoulder Rotation Range and Strength in Healthy Individuals

Effects of Artificial Forward Head and Neck Posture on Shoulder Rotation Range and Strength in Healthy Individuals

Background Although high-quality biomechanical evaluations, such as a three-dimensional motion analysis and electromyography, have been performed to verify the relationship between forward head posture (FHP) and shoulder dysfunction, most of the studies have mainly focused on neck and shoulder muscle activity or neck pain. Purpose To investigate the effects of artificial FHP on internal and external rotator strength and range of motion (ROM) of the glenohumeral joint using a dynamometer and inclinometer. Study design The study had a repeated-measures design. Methods ROM and muscle strength data were obtained from 29 participants. A standard incli-nometer and dynamometer were used to measure passive shoulder rotation ROM and muscle strength, respectively. Repeated-measures analysis of variance was used to compare ROM and strength data of the shoulder joint with and without FHP conditions and both shoulder sides. Results There was a significant difference in external rotation ROM values during passive ROM examination in FHP compared to no FHP (p<0.05). The internal rotation ROM value differed significantly according to the shoulder side (p<0.05). There was a significant difference in external rotator maximal strength values between FHP and no FHP (p<0.05). However, the shoulder sides and interaction effects between FHP conditions and shoulder sides for any ROM rotation values were not significant (p>0.05). Conclusions The results of this study indicated that FHP had a negative effect on rotation ROM and muscle strength of the shoulder joint, implying that it may act as a factor causing musculo-skeletal problems in the neck and shoulder region. Therefore, maintaining the correct head posture is important not only for intact of the neck but also for the health of the shoulder joint.