 Physical methods that increase blood flow in the leg veins are effective for reducing venous thrombosis in high-risk hospitalized medical and surgical patients. These methods include: high intensity electrical calf stimulation during surgery, graduated compression stockings and intermittent pneumatic compression of the leg or foot. Of these, only graduated compression stockings, which are not very effective, can be used after hospital discharge. Graduated compression stockings, however, cannot be adapted to fit all leg shapes, may be improperly applied, have a tendency to slip down the leg and are found to be uncomfortable by many patients. High intensity electrical calf muscle stimulation is painful and can only be used during general anesthesia. AC powered external pneumatic compression can only be used while the patient is fully immobilized. Thus, alternative convenient methods are needed which can be used both in the immobilized and partly mobile patient, particularly after hospital discharge. 