A recent study was published in JOSPT that examined stiffness in the cervical spine in those with nonspecific neck pain and asymptomatic individuals. The results revealed a difference in stiffness between the two groups. This should come as little surprise to those with manual therapy background, but the methods may raise some concern. For example, the age range was quite large (18-55), which may allow for significant differences in normal "stiffness" based on age-related degeneration. Interestingly, a standardized device was used for measuring how much force was required to move a segment. While it helps to consistently apply the same force in assessment (reducing inter- and intra-rater reliability), the validity of what should constitute stiffness isn't as thoroughly established. However, the presence of a significant difference in stiffness still warrants inclusion of these results in our clinical reasoning.
Why there is a difference in stiffness isn't as clear. One theory is that with the perceived "pain," there is an increased level of tone in the surrounding muscles, limiting the motion at the spinal segments. What should be noted, however, is that there was no correlation between the magnitude of stiffness and the level of pain. This may be explained by modern pain science theory, where amount of dysfunction doesn't typically match the perceived amount of pain.
What is the impact of this study to us? It may be unlikely that we, as therapists, can manually detect the presence of stiffness in the cervical segments. That doesn't mean the findings are insignificant. The fact that there is a difference between the groups suggest there is potential for future assessment. Also, it appears to be another sign to enhance some previous research regarding the benefit of manual therapy combined with exercise improving mechanical neck pain. With patients with nonspecific neck pain demonstrating stiffness in the cervical spine, we should consider using a method to improve mobility restrictions in our plan of care. Identifying restrictions can be difficult, but using a standardized examination format can enhance our ability to detect overall mobility restrictions.
Ingram LA, Snodgraass SJ & Rivett DA. (2015). Comparison of cervical spine stiffness in individuals with chronic nonspecific neck pain and asymptomatic individuals. J Orthop Sports Phys Ther. 2015 Mar;45(3):162-9.
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