LAUSR

LEVEL OF EVIDENCE: 3B SUMMARY Background. Muscle endurance is an important factor to maintain the proper posture. Improper posture in head and neck may alter muscle endurance in other segments of the vertebral column. This cross-sectional study was first aimed to compare the trunk muscle endurance in two groups of people with and without forward head posture. The second aim was to explore the relationships between forward head posture and trunk muscles endurance. Methods. Ninety seven participants (70 males and 27 females; mean age = 23.30 yrs.; mean body mass index = 22.76 Kg/m2) were assigned to two groups of people with forward head posture and people without forward head posture based on the amount of craniovertebral angle measured by photogrammetry technique. The endurance of trunk flexor, extensor and side-flexor muscles was measured in seconds and compared between groups. Results. The endurance of trunk muscles was significantly lower in the forward head posture group compared to control group (P < 0.05). There were also negative relationships between the severity of forward head posture and the endurance of trunk muscles (P < 0.05). Conclusions. The low endurance of trunk muscles in the presence of forward head posture may lead to poor muscular control of the spine and may predispose people to pain and disability in the future not only in the neck but also in the other spinal segments.