Mechanostat

The Mechanostat is a model describing bone growth and bone loss. It was promoted by Harold Frost and described extensively in the Utah Paradigm of Skeletal Physiology in the 1960s. The Mechanostat is a refinement of Wolff's law described by Julius Wolff (1836–1902).

According to the Mechanostat bone growth and bone loss is stimulated by the local mechanical elastic deformation of bone. The reason for the elastic deformation of bone is the peak forces caused by muscles (e.g. measurable using mechanography). The Adaptation (feed-back control loop) of bone according to the maximum forces is considered to be a lifelong process. Hence bone adapts its mechanical properties according to the needed mechanical function – bone mass, bone geometry and hence bone strength (see also Stress-strain index, SSI) is adapted according to the every-day usage / needs.

Due to this control loop there is a linear relationship in the healthy body between muscle cross sectional area (as a surrogate for typical maximum forces the muscle is able to produce under physiological conditions) and the bone cross sectional area (as a surrogate for bone strength).

These relations are of immense importance especially for bone loss situations like in osteoporosis, since an adapted training utilizing the needed maximum forces on the bone can be used to stimulate bone growth and hence prevent or help to minimize bone loss. An example for such an efficient training is vibration training or whole body vibration.