Hi, sorry for what may be a long-winded question!
I think we can be pretty confident that beliefs can influence disability and function through a fear-avoidance process. For example, someone gets an unnecessary MRI scan for back pain. This shows “disc degeneration” and other changes, and this causes the person to disengage in physical activity out of fear of making the problem worse. Then we have beliefs influencing pain indirectly through a fear avoidance mechanism. For example, someone is told by a health professional that their knee is “bone on bone” caused by “wear and tear”. This person then exercises less in order to reduce “wear and tear”. We know that exercise has a positive effect on knee pain, therefore this person stops benefiting from the positive effect of exercise on knee pain.
But what about beliefs directly influencing or causing a pain experience? We have evidence from statin trials that just believing that you’re taking a statin can cause muscle pain. We have evidence that if muscle soreness provokes more of a fear response, you are likely to report more pain from exercise-induced muscle soreness. But what about beliefs about exercise? For example, if you believe that an upright row is going to be a painful or uncomfortable movement because of "impingement ", are you more likely to experience pain during the exercise? Because the brain is more likely to perceive the movement as threatening. Another example could be believing that lower back rounding during the squat causes low back pain. Or does being told that your knee is “bone on bone” by itself increase pain?
This seems like something that would be fairly straightforward to test. Take two groups, prime one group with a low back fear- mongering information session. I.e, you must protect your spine, you must keep a neutral spine, spinal flexion is a mechanism for disc herniations, your discs are like a jelly-donut etc, and prime the other group with either no information about low back pain, or more optimistic information. Then measure their pain during a squat or deadlift training session.
Looking forward to hearing your thoughts on this or if you are aware of any studies that are similar to the above.