Standard anticoagulation therapy for acute deep vein thrombosis (DVT) reflects the current short term focus on preventing pulmonary embolism (PE) and recurrent DVT. Despite standard care, 25% to 50% of patients with DVT progress to the chronic post-thrombotic syndrome (PTS) resulting in significant disability, loss of productivity, and healthcare costs. The investigators postulate that a supervised exercise program in patients with acute DVT could increase lower extremity venous flow, accelerate thrombus resolution, and thereby decrease the risk of PTS. If the patient is unable to perform exercises, NMES (neuromuscular electrical stimulation) will be used to induce contraction of the muscles of the lower extremities.