Corrective exercise is the use of movements and/or postures to produce desirable changes in movement strategies, thereby minimizing or eliminating compensation and producing efficient movement patterns.
The body will always take the short term reward despite the potential for longer term punishment. For example, if your patella [knee cap] is not tracking properly and leading to low-grade irritation and pain (punishment), you alter your gait to avoid the provocative motion (short term reward). But as a result, the rest of the way you move is affected and can result in potential damage elsewhere (punishment). Slouching in a chair (short term reward) is another example. The reduced effort required for slouching takes precedent over the stress applied to the tissue during that moment in time and cumulatively. The goal of corrective exercise is to reduce muscular dysfunction, pain and imbalances in order to help you move and feel better.