In rehabilitation settings such as sports and physical therapy clinics, the body is often viewed as functioning in interconnected segments, for example, your arm, your shoulder, and your spine. The theory behind this is that movement of one part affects the others via a chain reaction. Here is an example:
When you walk, you step forward with one leg, then bring your trunk over that leg to move ahead. As the leg moves forward, it brings your pelvis on that side with it. In turn, this causes the pelvis on the other side to rotate back. And, your spine turns in response to both the leg and the pelvis as they extend to move you forward in space. This is the kinetic chain in action.
In rehabilitation, there are back exercises that work your muscles in closed kinetic chain movement. This type of exercise will strengthen muscles of the trunk or core, and will help to stabilize your posture.
Kisner, C., & Colby, L.A. (2002). Therapeutic Exercise: Foundations and Techniques.Philadelphia: F.A. Davis Company.