This research aimed to measure the connection between neck movement and the levels of pain and disability experienced by people with neck pain. The study focused on what is called "neuromusculoskeletal neck pain," which is pain originating from the nerves, muscles, or bones and joints of the neck.
Researchers wanted to understand the relationship between two specific things. The first is "cervical active range of motion." "Cervical" refers to the neck portion of the spine. "Active range of motion" is how far a person can move their own neck in different directions—forward, backward, side to side, and twisting—without any assistance. This movement is measured by a clinician. The second is "patient-reported outcomes," which are measures of pain and disability that come directly from the individuals themselves, often through questionnaires or rating their pain on a scale.
To do this, the researchers conducted a "systematic review" and a "meta-analysis." A systematic review involves a thorough and structured search for all existing research on a specific topic. A meta-analysis is a statistical procedure that combines the numerical data from these individual studies to calculate an overall result. This approach can provide a more comprehensive view than a single study alone. The plan for this research was publicly registered in a database called PROSPERO to ensure transparency.
The researchers searched six scientific databases and other sources (known as "grey literature") for relevant studies published up to December 2024. They included "observational studies" that reported "cross-sectional correlations." This means the studies looked at a group of adults with neck pain at a single point in time to see if there was a statistical link between their active neck movement and their self-reported pain and disability.
For each study they found, the researchers assessed its "risk of bias," which is the potential for flaws in a study's design or methods that could lead to inaccurate conclusions. They then performed eight separate meta-analyses using a statistical method called a "random-effects model," which is designed to combine results from studies that may have some natural variation between them. They also investigated reasons for differences between the studies' results by performing "subgroup analyses" (comparing groups like those with recent pain versus long-term pain, or whiplash versus pain from other causes) and "meta-regressions" (examining factors like participant age, sex, publication year, and risk of bias). Finally, the overall certainty of the evidence was rated using a formal system known as GRADE (Grading of Recommendations Assessment, Development and Evaluation).
The review included 45 separate studies, with a combined total of 3,494 participants. The results of the meta-analyses showed a consistent "negative correlation" between neck movement and patient-reported pain and disability. A negative correlation means that as one thing goes up, the other goes down; in this case, as a person's ability to move their neck decreased, their reported levels of pain and disability increased.
This statistical correlation was found to be "small to moderate" in strength for all directions of neck movement. The correlation values ranged from -0.21 to -0.34 (on a scale where 0 is no correlation and -1.0 is a perfect negative correlation). The connection was found to be stronger in people with "acute" (recent and short-term) neck pain and in those with "whiplash-related" neck pain, which is caused by a traumatic event like a car accident.
The researchers found "substantial heterogeneity" in the results, meaning there was a large amount of variation among the findings of the 45 different studies. A statistic used to measure this, called I², was between 67% and 91%, indicating high inconsistency. Some of this variation could be explained by the duration of the participants' symptoms and the original cause of their neck pain. The overall certainty of the evidence was rated as "very low." This was due to the risk of bias in the original studies, the inconsistency of their results, and statistical "imprecision" (a lack of certainty in the numerical estimates).
In conclusion, the findings show that there is a modest relationship between how far a person can move their neck and the amount of pain and disability they feel. This association is more pronounced in individuals with recent or trauma-induced neck pain. However, these findings must be interpreted with caution because the overall quality of the available evidence is very low. The researchers recommend that future studies use standardized, consistent methods for measuring neck movement and be of higher quality in order to provide more reliable information for clinical practice.