Given the complexity and many factors of a given individuals pain experience, how could causation of pain be directly connected in a legal sense. Say for instance, an individual reports that they have back pain after lifting an object. Can anyone definitively state with a high degree of certainty that the pain is from lifting the object? The question seems unanswerable to me given the potential for confounders like prior injury, development of non specific mechanical low back pain, other factors etc.
I’m not sure that I fully understand this question.
If a person was pain-free prior to an activity, and develops pain during/immediately after the activity in a specific location that is plausibly impacted by the activity, it is often reasonable to make this presumption. As far as what to do about it (both in the immediate sense and for future risk reduction), this is where folks will often disagree.
Prior injury is well-known to increase the risk for subsequent injury, but it would be silly to dismiss an immediate temporal relationship with activity and invoke a spontaneous, coincidental flare-up as an explanation.