I can tell you some advices that have worked in my life in relation to this, in a work that also demands a lot of work with the hands like being a musician.
There is people with more resistance and people with less, naturally, because of the type of body you have, within this there are important advices like aaalways warming-up the muscles involved in the work, as gently and efectively as you can, so they start the work when they are ready and not before, also while you are in the activity, try to make the movements precissely, like, you don't want to generate extra tention, extra strenght, only the neccesary ammount of effort for the task you are doing, there is a huge difference between doing a movement 3 times in a row with no care, with no awareness, and thereforce generating more tention more effort and more harm, and doing the movement 3 times with the exact expression that the movement requires, and also paying attention to how the rest of the body is behaving, if it's all tense or it has awareness. Awareness meaning that it's relaxed and confortable.
The harm comes when you are doing something that is not natural in the body, for a long period of time, and in the wrong way. Sometimes the wrong way is the task itself, because it's unnatural to be in that position doing that for so long, however the body can addapt, to certain point. Sometimes you can do an unnatural task for your body in a natural way, for example using the correct tecnice while doing the task, the correct tecnice is always the most natural movement for the body. So there is no easy solution for a job that requires 8 hours of daily effort, I have friends that wanted to practice guitar for 7 hours a day and end hurting themselves. Thereforce the best you can do to prevent harm in your body is warming-up, not creating extra tention, getting to know the movement so you can do it gently, trying to make natural movements, and if still your job hurts your body I really reccomend you to quit rather than making a permanent damage to your body. Take care