Inclusion Criteria:  Men and Women with T1DM  Insulin pump users  Exclusion Criteria:  Metabolic instability as evidenced by hospitalizations for diabetes or other diabetes-related complications (e.g., diabetic ketoacidosis and hypoglycemic seizures) within the preceding three months; Severe macrovascular disease, as evidenced by severe peripheral artery disease; history of myocardial infarction, heart failure, thromboembolic disease, or unstable angina; uncontrolled hypertension; abnormal resting EKG; Maximal exercise stress test with significant brady/tachy arrhythmia, ectopic beats, bundle branch block, or signs of acute ischemia; Severe microvascular disease as evidenced by history of vision-threatening proliferative or non-proliferative retinal disease; kidney disease; Any uncontrolled non-musculoskeletal condition that would limit the subject's ability to participate in the exercise program (e.g., chronic obstructive airways disease); Musculoskeletal conditions such as neurological or orthopedic conditions affecting lower limb strength and mobility (e.g., stroke; insensitive foot); Pregnancy; Documented medical condition or physical impairment that is judged by the health care practitioner to contraindicate exercise.