Inclusion Criteria:

          1. Age ≥ 18 years

          2. Post- menopausal and planned to initiate an AI

               1. Post- menopausal defined as ≥ 60 years of age, prior bilateral oophorectomy, or
                  age ≥ 50 and absence of any menstrual periods in the last 12 months.

               2. Chemical ovarian suppression is not allowed.

               3. Prior use of a SERM and now switching to an AI is allowed.

          3. Diagnosis of DCIS or stage I, II, or III breast cancer

          4. Completion of all primary therapy for breast cancer, including surgery, radiation, and
             chemotherapy. Patients must be ≥ 21 days from chemotherapy completion and ≥14 days
             from radiation completion. Ongoing HER2 targeted therapy with trastuzumab or
             pertuzumab is allowed. Neratinib, immunotherapy, or CDK4/6 inhibitor therapy is not
             allowed.

          5. Baseline T score > - 2.0 on DXA

          6. Body weight less than 275 lbs., as dictated by the weight limit for the LIV platforms

          7. ECOG performance status of 0-1 at the time of study enrollment

          8. Informed consent and authorization of the release of health information must be
             obtained according to institutional guidelines

          9. Physically able to stand unassisted for 10 minutes at a time

         10. Currently not participating in regular exercise (defined as less than 60 minutes of
             moderate to vigorous exercise per week measured by the RPAQ questionnaire)

        Exclusion Criteria:

          1. Unwilling to co-enroll onto the companion FIT core study (IRB study #1707550885)

          2. Diagnosis of other disorder affecting bone function or turnover, such as Paget's
             disease, renal osteodystrophy, parathyroid disorders, vitamin D
             deficiency/osteomalacia, chronic renal disease (Cr > 1.4)

             a. Vitamin D must be corrected to ≥ 20 ng/ml prior to study enrollment. History of
             vitamin D deficiency is allowed.

          3. Prior history of non-traumatic, fragility bone fracture

          4. Any muscle or neuromuscular disorder affecting muscle function, such as muscular
             dystrophy, myositis, or amyotrophic lateral sclerosis

          5. Use of bisphosphonates or denosumab within the prior 12 months

          6. History of retinal detachment

          7. Current or planned pacemaker

          8. Current or planned cochlear implant

          9. Any condition precluding power protocol participation (i.e. riding a stationary
             bicycle), including: NYHA class III or IV congestive heart failure, uncontrolled
             angina, myocardial infarction in the prior 12 months, orthopedic surgery in the
             previous 6 months or plans for orthopedic surgery during the study period, chronic
             uncontrolled pulmonary conditions such as uncontrolled asthma (symptoms > 2 days/week)
             or dyspnea requiring oxygen, symptomatic peripheral vascular disease, or any other
             comorbidity that would interfere with the ability to complete and comply with the
             protocol in the opinion of the investigator

         10. Locally recurrent or metastatic breast cancer

             a. History of prior treated malignancies, other than breast cancer, that are now
             stable, are in remission, and do not require active therapy, are acceptable.

         11. Patients requiring chronic anticoagulation are excluded from participation in the
             optional muscle biopsy collection.

         12. Women undergoing ovarian suppression with drug therapy are excluded