Force not converted into movement causes damage.

If you rely mainly on your will power, you will develop your ability to strain and become accustomed to applying an enormous amount of force to actions that can be carried out with much less energy, if it is properly directed and graduated.

Both these ways of operating usually achieve their objective, but the former may also cause considerable damage. Force that is not converted into movement does not simply disappear, but is dissipated into damage done to joints, muscles, and other sections of the body used to create the effort. Energy not converted into movement turns into heat within the system and causes changes that will require repair before the system can operate efficiently again.

Moshe Feldenkrais in "Awareness Through Movement" page 58