The Bottom Line: Neck Flexion: What are the Consequences?

In the US, 90% of adults own a mobile device and spend more than 3 hours on average a day maintaining a prolonged neck flexion posture of 45 degrees or more to use them. Certified ergonomist Blake McGowan shares the results of a study that examined the biomechanical consequences of this “text neck” posture in the video below.

References: Barrett JM, McKinnon C, Callaghan JP. Cervical spine joint loading with neck flexion. Ergonomics. 2019 Oct 15:1-8.

Video Transcript

In the United States, 90% of adults own a mobile phone and spend more than three hours a day using their device. This means that most people maintain a prolonged neck flexion posture of 45 degrees or more while reading their screen on this device, and this posture has been strongly implicated as a primary risk factor for neck pain disorders such as text neck.

So, what are the biomechanical consequences of prolonged neck flexion? Well, recently in 2019, Jack Callahan and colleagues from the University of Waterloo developed a complex biomechanical model of the neck in order to determine the compressive as well as the shear forces during prolonged neck flexion postures at 45 degrees.

So, what did they find? First, when the neck is flexed at 45 degrees, the compressive forces increased 1.6-fold, and the shear forces increased almost fourfold. Second, the combination of the flexed neck posture, the large compressive forces, and the large shear forces increases the risk of disk herniation.

So, what does this mean? What’s the bottom line? The bottom line is that prolonged neck flexion postures alter joint capabilities, increase joint forces, and is considered a primary risk factor for neck pain disorders such as text neck.