The written agreement of the subjects will be obtained after information on the aims, nature and possible risks of the study.~Before inclusion, the volunteers will be subjected to a medical check-up at the Nutritional Exploration Unit which includes an examination of personal and family history and current drug treatments, as well as a standard medical examination and a blood test for a biological check-up. Also, the volunteers will be subjected to a check-up with dietetics. Compliance with the inclusion/ exclusion criteria will be verified during this review. Volunteers included in the protocol will go to the Sports Medicine service, or the Nutritional Exploration Unit, or the Clinical Pharmacology Center (CPC) to perform the 11 interventions.~The study will be conducted in 6 periods:~T0 : A standard maximal exercices test performed on an cycloergometer to determine the subject's abilities (VO2) and to set the target powers of the experimental clinical tests. This test will take place in the Sports Medicine service.~T1 : A period of habituation to eccentric exercise, starting from 6 sessions of habituation realized over a period of 15 days where the sessions are gradually increased in duration and intensity. This test will take place in the Sports Medicine service. Before each session of habituation, a Visual Analogue Scale (VAS) will be performed. If the result will be greater than or equal to 3, the session will be rescheduled for another session after 48 hours.~T2 & 3 : Two tests of effort, sub-maximal, progressive, carried out in eccentric mode and concentric mode (each spaced at least 48 hours) to determine the carbohydrate and lipid oxidation rates. Both tests will take place in the Sports Medicine service. The day before each visit, the evening meal will be standardized and eaten before 8 pm. Moreover, the day of both visits, the breakfast will be standardized and eaten 2 hours before the subject will go to Nutritional Exploration Unit.~T4 & 5 : Two exercises tests during 30min performed at 30% VO2max and followed by indirect oxygen calorimetry (with canopy) extended over a period of 6 hours to measure the energy expenditure, the nature of the oxidized substrates (carbohydrates and lipids) and oxidation rates. The day before each visit, the evening meal will be standardized and eaten before 8 pm. Moreover, the day of both visits, the breakfast will be standardized and eaten 2 hours before the subject will go to Nutritional Exploration Unit. In addition, for each kinetic, 7 blood samples will be collected at several times. On these samples, insulin and blood sugar will be measured.
Main objective of this clinical trial is to compare the oxidation rates of main carbohydrate and lipid substrates during exercises carried out in eccentric dynamic pedaling mode on a cycloergometer compared to concentric exercises (classic pedaling) at the same oxygen consumption (VO2).~The hypothesis is that lipid oxidation during an eccentric exercise is higher than lipid oxidation during a concentric exercise, done in humans at the capacity of 30% of VO2max.