Significance of Estrogen Status for Muscle Function, Physical Fitness, and Physiological Health Parameters - a Comparison of Age-matched Groups of Women Before and After Menopause.

Inclusion Criteria: * Regular menstrual bleeding (21-35 days cycle). * At least 9 menstrual cycles the last year * Age \>47 years old * BMI 20-30 Exclusion Criteria: * Only premenopausal women: Follicular stimulating hormone \> 30 mmol/L * Systematic strength training during the last year (\> 1 strength training session per week) * Systematic high intensity cardiovascular training during the last year (\<2 times per week) * Injuries to the legs which may prevent participation in the physical training program * Magnetizable metals or electrical devices implanted in the body, such as a pacemaker * Use of medication that can influence the effect of immobilization and/or training * Muscular or joint disorders which may affect the results * Metabolic diseases (such as diabetes and cardiovascular diseases) * Previous or present liver or cancer disease * Current or previous thrombosis * Porphyria * Epilepsia * Systemic autoimmune disease * Edema * Smoking or use of other nicotine containing products * Claustrophobia * Addictive behavior, defined as abuse of cannabis, opioids, or other intoxicating substances. * Lack of ability to cooperate * Blood parameters out of normal range at the health check * Blood pressure above 140/90 mmHg