The association of hormone therapy with impaired gains in lower body strength could be explained by musculoskeletal events (e.g., myalgia, joint stiffness, tingling) in breast cancer patients receiving adjuvant aromatase inhibitors and tamoxifen [40], and the high prevalence of arthralgia during aromatase inhibitor treatment in early breast cancer patients [41,42]. This evidence concerns the gene CYP19A1 and breast carcinoma.