The Effects of Forward Head Posture on Neck Extensor Muscle Thickness: An Ultrasonographic Study.

OBJECTIVE

This study aimed to compare neck extensor muscle thickness, thickness changes, and strength between participants with forward head posture (FHP) and controls with normal head posture (NHP).

METHODS

Twenty college students with FHP (mean age 21.30 ± 2.36 years) and 20 students with NHP (mean age 21.85 ± 2.78 years) participated in this case-control study. The thickness of neck extensor muscles was measured at rest and at maximal voluntary isometric contraction (MVIC). In addition, the craniovertebral angle (CVA) was calculated. To compare thickness changes between the 2 groups and among 5 muscles, a 2-way repeated measures analysis of variance was applied. In addition, Pearson's correlation test was performed to investigate the relationship between neck extensor MVIC and CVA.

RESULTS

The FHP group demonstrated lower MVIC compared with the NHP group (P = .03). Semispinalis capitis showed the smallest thickness changes during neck extensor MVIC in FHP compared with the controls (P < .001). However, no significant difference in terms of muscle thickness was observed between the 2 groups at the state of rest (P = .16-.99). A positive association was also found between the MVIC and CVA (P = .02).

CONCLUSIONS

Semispinalis capitis had less thickness changes during MVIC of neck extensors in individuals with FHP compared with those with NHP. This indirectly implies lower activity of this muscle in FHP condition. This study finding may help researchers develop therapeutic exercise protocols to manage FHP.