Abstract: An apparatus and method for micro-exercise apply piezoelectric stress to cells of a bone mass by inducing voltages in the bone mass. Application of dynamic, electromagnetic fields passing through the conductive bone mass induce currents and voltages locally in and around cells or groups of cells. The cells respond to the combination of mechanical stress and strain by building themselves up as they would if they had been subjected to the stress and strain of conventional exercise. Thus, micro-exercise at a cellular level of the bone mass can be stimulated as if the stress and strain had been applied to the entire bone structure of which the smaller cellular portions are constituent parts. In combination with casts or splints, the sources of electromagnetic flux may be embedded in the frame or solid structure, the protective padding added for comfort, or both.