Imagine that all these pathways are written in Chalk. Eventually injury, or jammed joints, or poor neural mapping (sensory motor amnesia) smudge the Chalk. The movement path, all things considered, isn’t clear; You lose full range of motion in your shoulder, for example, or your hips fire but can’t relax.
This is basically why we are tight; Or weak; Or can’t perform certain movements. Your signal is imperfect, or non existent. You’ve smudged the Chalk, hence you can’t move properly.