We’re going to try to avoid turning this into a pain science blog, but it’s important to know that the experience of pain is complex and often comes from a combination of biomechanical and psychosocial factors.
What that means in English, is that many people experience pain, because their nervous system is warning them about a perceived threat or potentially “unsafe” position. However, this does not always mean that what you are doing will result in an injury (aka tissue damage).
One reason why strength training may help with pain is because pain is often the result of heightened sensitivity from your nervous system. When something is more sensitive, it’s more likely to create the experience of pain.
When you thoughtfully expose these areas to more load in a way that the nervous system doesn’t find threatening, it decreases the sensitivity, which may mean less pain overall.
Getting stronger = a signal of safety to your nervous system, because your nervous system can sense that your joints are under control.
Beyond that, it’s now thought that injuries are more likely to occur if you are unprepared for a movement and you overload a joint. Strength training can help with this, because it makes you stronger in more ranges of motion, which decreases your likelihood of overloading something.
Finally, if you’ve experienced pain during strength training, there is often an issue with the application and a few simple tweaks to how you perform the exercise (e.g. changing the weight, speed, number of repetitions, or body position) can help you have a more positive experience with less joint discomfort.