Introduction:
Forward head posture (FHP) is commonly seen in subjects with chronic neck pain (CNP) and is associated with respiratory function limitations. Therefore, the main aim of this study was to assess the effect of FHP compared with normal head posture (NHP) on diaphragmatic excursion in subjects with non-specific CNP.

Methods:
Overall, 30 subjects with CNP aged 35–45 years were recruited for this study and divided into 2 equal groups: the FHP group and the NHP group. The inclusion criteria were non-specific CNP duration of 3 months, presence or absence of FHP, FHP confirmed with a craniovertebral angle of < 50°, and male or female sex. The exclusion criteria involved cervical disc problems, cervical spondylosis, traumatic neck pain, chest disease or heart failure, neurological disorders affecting the diaphragm, obesity, and smoking. First, the craniovertebral angle was assessed for subject selection; then, the diaphragmatic excursion and the neck disability index (NDI) were established as the main clinical outcomes of the study. Unpaired t-test was used for statistical analysis.

Results:
The diaphragmatic excursion was lower in the FHP group than in the NHP group (57.00 ± 15.63 vs. 67.60 ± 15.18; p = 0.070), with no significant difference between the 2 groups. NDI did not differ significantly between the groups.

Conclusions:
We suggest that FHP may be related to reduced diaphragmatic excursion in subjects with non-specific CNP. The multimodal approaches to physiotherapy management of non-specific CNP with FHP may consider our suggestion.