Inclusion Criteria:  Healthy female volunteer (see below the description of medical tests and laboratory analysis performed at the selection visit), Age 20 to 40, No overweight nor excessive thinness with BMI (weight Kg/ height m2) between 20 and 26, Height between 158cm and 180 cm, Regular menstrual cycles and cycles lasting between 20 and 35 days, Without oestroprogestative contraception (i.e., oral progestative contraception, IUDs, implants or absence of contraception are allowed), Certified as healthy by a comprehensive clinical assessment (detailed medical history and complete physical examination): in particular, free from any chronic disease or any acute infectious disease or cardiovascular, neurological, ENT (especially orthostatic hypotension and vestibular disorders), orthopaedic or musculoskeletal disorders,  Fitness level assessment:  if age < 35 years: 35 ml/min./kg < VO2max < 55 ml/min./kg, if age > 35 years: 30 ml/min./kg < VO2max < 55 ml/min./kg, Non active smokers, No alcohol, or drug addiction, and no medical treatment (with the exception of the aforementioned accepted means of contraception), Covered by a Health Insurance System, Having signed the informed consent, Free from any engagement during the study.  Exclusion Criteria:  Any history or presence of clinically relevant cardiovascular, neurological or ENT (especially orthostatic hypotension and vestibular disorders), any chronic disease; any acute infectious disease, in particular, Symptomatic orthostatic hypotension whatever the decrease in blood pressure, Asymptomatic postural hypotension defined by a decrease in SBP equal to or greater than 20 mmHg within 3 minutes when changing from the supine to the standing position, Cardiac rhythm disorders, Hypertension, Chronic back pains, Vertebral fracture, scoliosis or herniated disc, Glaucoma, Self-reported hearing problems, History of migraines, History of hiatus hernia or gastro-esophageal reflux, History of thyroid dysfunction, renal stones, diabetes, History of head trauma, Abnormal result for lower limbs echo-doppler, History of genetic muscle and bone diseases of any kind, Past records of thrombophlebitis, family history of thrombosis or positive response in thrombosis screening procedure (anti thrombin III, S-protein, C-protein, factor V Leiden mutation and the mutation 20210 of the prothrombin gene), Women who have stopped breastfeeding within 2 months before the start of the study, Women who have undergone an abortion within 3 months before the start of the study, Irregular menstrual cycles or cycles lasting less than 20 days or more than 35 days, Oestroprogestative contraception, Recent implementation or change in hormonal contraceptive (in the last 6 months), Bone mineral density: T-score ≤ -1.5, Poor tolerance to blood sampling, Having given whole blood (more than 8ml/kg) in a period of 8 weeks or less before the start of the experiment, or having given whole blood more than 3 times in the past year, Significant history of allergy, especially no dermatological allergy, History of food allergy, Significant anomaly detected in the biological analysis, Positive reaction to any of the following tests: HVA IgM (hepatitis A), HBs antigen (hepatitis B), anti-HVC antibodies (hepatitis C), anti-HIV1+2 antibodies, Vegetarian or vegan, Refusal to give permission to contact her general practitioner, Subject who, in the judgment of the investigator, is likely to be non-compliant during the study, or unable to cooperate because of a language problem or poor mental development, Subject already participating or in the exclusion period of a clinical research, Subject who has received more than 4500 Euros within 12 months for being a research subject, Subject who cannot be contacted in case of emergency,  MRI contraindications  History or active claustrophobia, Osteosynthesis material, presence of metallic implants or any other contra-indication for MRI, Allergy to Gadolinium.  Vulnerable persons according to law "Code de la Santé Publique" (L1121-5 to L1121-8) :  Pregnant women (urine pregnancy test performed at the selection visit and on the day of arrival in the facility), Women during childbirth and breastfeeding mothers, Persons deprived of their liberty by an administrative or judicial decision, Persons under involuntary psychiatric care, Persons admitted in a health or social establishment for purposes other than research, Minors, Adults subject to legal protection (subject under guardianship or trusteeship) or unable to express their consent.