The Effects of Traditional, Menstrual Cycle Phase-based, and Symptom Autoregulatory Resistance Training Prescription on Strength, Power, and Hypertrophy Adaptations in Healthy Female Adults

This study aims to compare the effects of traditional training prescription (TRAD), menstrual cycle phase-based training prescription (MCP), autoregulatory prescription based upon perceived menstrual cycle symptoms (AUTO), and a free-living control (FLC) on changes in muscular strength, power, and hypertrophy across an eight-week training intervention in healthy females. The study was a randomised controlled trial study design. For each participant, the study duration spanned four menstrual cycles, with participant's individual timeline determined by their menstrual cycle length. This included two baseline cycles, followed by two training cycles which involved 22 resistance training sessions completed across approximately eight weeks. The training program followed a block periodisation model, which consisted of two four-week mesocycles of increasing volume, with an unloading week during each week of testing. The initial four weeks involved higher training volumes (e.g., 10 repetitions) performed at moderate intensities (i.e., 53-68% 1RM), while the subsequent four weeks emphasised maximal strength with moderate training volumes (e.g., 5 repetitions) performed at higher intensities (i.e., 61-80% 1RM). To align the training program with each participant’s menstrual cycle, the first training session of each block was initiated by the onset of menstrual bleeding, and testing occurred during the final week of the cycle. Furthermore, sessions were scheduled according to follicular and luteal phases, with the luteal phase starting the day after ovulation. A combination of calendar-based counting and urinary ovulation testing was used to determine follicular and luteal phases. For the TRAD and MCP groups, all repetitions, sets, and intensities were prescribed for each exercise. However, the MCP group performed higher frequencies of training during the follicular phase and lower frequencies of training during the luteal phase of the menstrual cycle (i.e., eight sessions during the follicular phase and three sessions during the luteal phase), while the TRAD and AUTO groups performed a more even distribution of training frequencies in both phases (i.e., six sessions and five sessions, respectively). For the AUTO group, participants were allowed to manipulate session intensity ±4% or 8% of 1RM (which subsequently altered total volume) based upon their perceived menstrual cycle symptoms. All training sessions lasted approximately 60 minutes and were supervised one-on-one by a qualified exercise professional. At least one day of rest was scheduled between sessions. However, due to interindividual variations in cycle and phase length, it was not always feasible to strictly adhere to this rest period between sessions. Each session consisted of six exercises, beginning with primary exercises (i.e., exercises that underwent 3RM strength testing; e.g., trap bar deadlift, bench press), followed by secondary compound exercises (e.g., split squats, shoulder press, rows) and auxiliary exercises (e.g., lateral raise, triceps extension, biceps curls). Training intensities for the primary exercises were prescribed using loads corresponding to a percentage of estimated 1RM. For secondary compound exercises, training was prescribed using the repetitions in reserve method, whereas auxiliary exercises were prescribed using repetition maximum zones. For all exercises, participants were instructed to control the eccentric phase and to execute the concentric portion using maximal intent. Participants were required to complete >90% of the total number of workouts to be included in the analysis.