The main goal of this study is to examine how sex hormones and low energy availability affect the concentrations of bone remodelling markers at rest and after a running protocol. The research questions to be addressed are: 1: Does the ovarian hormone profile influence serum bone marker concentrations in women exercising resting and in response to to exercise? 2\. Are there differences in response to low energy availability in bone marker concentrations between eumenorrhoeic female athletes and oral contraceptive users? 3: Is the response of bone markers affected by different exercise stimuli: endurance or aerobic endurance? 4: Do bone markers return to baseline levels after 24 hours of high energy availability diet after 6 days of low energy availability?
To achieve the aim of the study, there will be two experimental groups - e.g. eumenorrhoeic females and oral contraceptive users - who, after screening, will be randomly assigned to a low- or high-energy diet. After 6 days on this diet, the participant will undergo an intervallic running protocol and blood samples will be taken before and after the test. The following month the participant will do the other type of diet.
Study Type
INTERVENTIONAL
Allocation
NON_RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
NONE
Enrollment
22
Participants follow 6 days of a low-energy availability diet. The kilocalories of each diet are prescribed individually based on their fat-free mass.
Participants follow 6 days of a high-energy availability diet. The kilocalories of each diet are prescribed individually based on their fat-free mass.
Faculty of physical activity and sport sciences
Madrid, Comunity of Madrid, Spain
Concentration of bone metabolism biomarkers
Concentration of procollagen type I N-propeptide (P1NP), cross-linking telopeptide of type I collagen (βCTX-1), paratyroid hormone, calcium, sclerostin, osteoprotegin, osteocalcin, bone alkaline phospatase, Receptor Activator for Nuclear Factor κ B Ligand (RANKL) measured in serum samples.
Time frame: immediately pre-exercise and immediately, 15 minutes and 24 hours post-exercise
Concentrations of other biochemical biomarkers
Concentrations of Triiodothyronine (T3), Albumin, Sex Hormone Binding Globulin (SHBG), etc. measured in serum
Time frame: Immediately pre-exercise and immediately, 15 minutes and 24 hours post-exercise
Concentrations of sex hormones
Concentrations of 17β-Oestradiol and Progesterone measured in serum.
Time frame: Immediately pre-exercise and immediately, 15 minutes and 24 hours post-exercise
Bone mineral density
Total, lumbar spine and femoral neck bone mineral density (g/cm\^2) measured by dual x-ray absorptiometry
Time frame: At the screening phase
Training status variables
Oxygen uptake at ventilatory threshold 1, ventilatory threshold 2, and maximal oxygen uptake (ml/kg/min) measured with a gas analyser.
Time frame: At the screening phase
Body composition variables
Fat mass (kg), fat free mass (kg), fat mass percentage, fat-free mass percentage (FFM), total mass (kg) measured by dual x-ray absorptiometry
Time frame: Immediately pre- and post-nutritional intervention (bioimpedance) and DXA at the screening
Body metrics
Height (cm)
Time frame: Measured at the screening phase
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