Exercise Overview
The kinetic chain refers to the interaction of the various sections of the body and how they influence one another. This is an important concept to understand in terms of your own performance and function.
For a simple example of this we can look at the shoulder region. If there is an issue going on at the shoulder joint itself whether rotator cuff, limited mobility etc we first look adjacently at the shoulder blade (scapula) and it's function. At the same time we must also consider the role that the elbow may play on that shoulder as there are muscles that cross both joints, also from a biomechanical aspect, a limitation in one of those may hinder the function of the other. So when looking at a particular region and want to improve it we should also consider adjacent regions.
This will hopefully help you make more sense of what exercises to try in regards to what areas you want to improve, meaning not just doing exercises for that area but also exercises for adjacent areas. This is not in reference to pain as pain can multiple factors, this is more so in reference to general movement and mobility.