Menstrual Cycle Phase Based Training

Participants will be required to track their menstrual cycle (MC) for a total of four MC's. MC tracking will be done via self-reported menstrual onset and ovulation strips. During the first tracking cycle participants will be asked to come in at three time points for blood draws to confirm hormone concentrations and familiarize them with the strength testing protocol. Following the tracking month participant legs will then be blocked randomized based on leg skeletal muscle mass and strength into one of four groups: non-exercise control (CON), exercise control (EX), follicular based training (FOL) and luteal based training (LUT). Participants will then be asked to come in \~2x per week (4-6x/menstrual cycle phase) for resistance training under direct supervision. Participants will be trained in unilateral leg extension and unilateral leg press. For legs randomized to the FOL and LUT group, training volume will be manipulated by changing the number of sets completed. The FOL group will train high volume (\~20+ sets per week) in their follicular phase and low volume (\~5 sets/week) in their luteal phase, the opposite will be true for the LUT group. Muscle biopsies will be taken both prior to and after training to assess changes in fiber cross-sectional area (CSA) and capillarization. Segmental body composition will be assessed both prior and post training using bioelectrical impedance analysis (BIA), dual x-ray absorptiometry (DXA), and vastus lateralis cross-sectional area and thickness. Muscle strength will also be assessed pre and post training using the isokinetic dynamometer, unilateral one-repetition maximum (1RM) leg extension and unilateral 1RM leg press.