TG and hypothyroidism: Three key observations in the literature informed this study: (1) previous research links low thyroid levels with a conversion from fast to slow fiber types [37] (although females with low thyroid hormones have a higher amount of type II than their male hypothyroidism counterparts [20]); (2) low estrogen such as seen in the menopause is synonymous with decreased lean tissue content [38, 39], lower physical performance [40], and animal work corroborates with these observation [41, 42]; (3) skeletal muscle is an estrogen-responsive tissue as it contains receptors for this ligand [43–47].