Biomechanics is the study of the mechanics of movement. Biomechanical failure is one of the main reasons for musculoskeletal pain. A faulty movement pattern over time can create eventual strain or pain which can lead to injury.
The imbalance caused due to muscle weakness and the lengthening or shortening of the muscles can create a huge biomechanical failure in the whole body. In simple term, the muscles which are supposed to work during a particular activity will not function where as it will be compensated or overworked by the surrounding muscle/muscle groups.
If you already have pain it is important to not only treat the tissue involved, but re-educate any movement pattern that has contributed to the problem. Each individual requires assessment to identify the factors contributing to their specific situation.