The purpose of this study is to conduct a 12-month randomized controlled trial comparing the effects of strength training exercise to stretching and relaxation exercise (control) on body composition (bone, muscle and fat mass), energy balance, bone turnover, and physical function (strength, power, gait, balance and self-report physical function and symptoms) in women who experienced premature menopause from chemotherapy for breast cancer.
Inclusion Criteria: * Diagnosed breast cancer stage I-IIIa * Completion of a chemotherapy regimen within the previous 5 years * Premenopausal status (9-12 menstrual cycles/year) at the initiation of chemotherapy * Complete absence of menstrual cycles for at least 6 months and within one year after starting chemotherapy OR confirmed menopause by blood tests conducted in the last 12 months prior to enrollment. Exclusion Criteria: * Presence of any known metastases * Clinically defined osteoporosis * Current or previous use of medications known to affect bone metabolism * Current regular participation (\>2x/wk for at least 30 min/session) in planned impact activities (i.e., volleyball, basketball), or resistance training * A medical condition, disorder, or medication that contraindicates participation in moderate intensity impact or resistance exercise