With around 80% of sedentary jobs, often requiring several hours of sitting bent over a computer screen, neck pain is a growing occupational risk. Smartphones and other devices have also caused people to bend their necks for long periods of time. But is bad posture only to blame?
In a recent study, researchers from Texas A&M University found that while poor neck and head postures are indeed the primary determinants of neck pain, body mass index, age and l The time of day also influences the neck’s ability to perform sustained or repeated movements. .
“Neck pain is one of the leading and fastest growing causes of disability in the world,” said Xudong Zhang, professor in the Department of Industrial and Systems Engineering at Wm Michael Barnes 64. “Our study highlighted a combination of professional and personal factors that strongly influence neck strength and endurance over time. More importantly, since these factors have been identified, they can then be changed so that the neck is healthier and pain is avoided or deterred. “
The results of the study are published online in the journal Human factors, leading journal in the field of human factors and ergonomics.
According to the Institute for Health Metrics and Evaluation’s Global Burden of Disease study, neck pain is ranked fourth among the leading causes of disability worldwide. One of the main reasons for neck pain has been attributed to lifestyle, especially when people spend long periods of time with their necks bent forward. However, Zhang said a systematic quantitative study was missing on how personal factors, such as gender, weight, age, and work habits, can affect neck strength and endurance.
For their experiments, Zhang and his team recruited 20 adult men and 20 adult women with no neck-related issues to perform controlled head-neck exercises in a lab. Instead of requiring participants to maintain a specific neck posture for a long period of time, similar to what might happen in the workplace, they performed head-to-neck exercises “from sustained exhaustion to exhaustion”.
“In the laboratory, conducting experiments where subjects perform long tasks with their necks can take several hours of data collection, which is not very convenient for the experimenters and, of course, for the participants in our study,” Zhang said. “To solve this problem, our experiments were strategically designed to mimic neck strain in the workplace, but within a shorter time frame.
In these exercises, subjects were seated and asked to wear an augmented helmet that allowed them to exert measurable force through the neck. Then the researchers asked them to keep their necks straight or keep their necks tilted forward or backward. In this position, force was applied to their head and neck on an adjustable frame. This effort was either at their maximum capacity half of it. Before the tests, the researchers noted their subjects’ ages, their body mass index and the time of day.
When Zhang and his team analyzed their data, they found that, as expected, work-related factors like head and neck posture play a very important role in determining neck strength and endurance. . But they also observed that while there was no significant difference between male and female subjects in neck endurance, body mass index was a significant predictor of neck endurance. Also, to their surprise, the time of day affected the neck’s ability to support effort without fatigue.
“It’s intuitive to think that during the day our necks get tired more and more because we use it more,” said Zhang. “But about half of our participants were tested in the morning and the rest in the afternoon. Also, some of the participants had day jobs and some at night. Despite this, we constantly saw the effect. of the hour on the neck. endurance. “
The researchers said their neck strength and endurance database is also needed to build advanced musculoskeletal biomechanical models of the neck, which can then be used to, for example, unravel specific neck muscles that are more vulnerable to injury.
“Looking to the future, we may have the data to start assessing whether patients recovering from neck injuries are ready to return to work based on their neck strength and endurance being within range. standard, ”Zhang said. “Additionally, engineers and designers could use our data to make wearable devices, like headsets, more ergonomic and less stressful on the neck.”
Other contributors to this work include Suman Chowdhury from Texas Tech University, and Yu Zhou, Bocheng Wan, and Curran Reddy from the Department of Industrial and Systems Engineering.
This research is funded by the National Institute for Occupational Safety and Health, which is part of the Centers for Disease Control and Prevention.