Frequency variations of strength training sessions triggered by the phases of the menstrual cycle.

The aim of the study was to compare the effects of two different models of altering the frequency of strength training sessions of females. The "regular training" (RT) consisted of one training unit every third day over the whole menstrual cycle. The "menstrual cycle triggered training" (MCTT) was characterized by workouts every second day in the follicular and about once per week during the luteal phase. In order to increase maximal strength (MS) the participants performed 3 sets with 12 reps each. Endogenous processes were controlled by measurements of body-temperature, control of the luteinizing-hormone peak, and by analysing serum hormone (estradiol, progesterone, testosterone, and cortisol) and sexual hormone binding globulin (SHBG) levels. MS and muscle cross-sectional area (MCA) of the quadriceps femoris were investigated. The result of the MCTT showed a clear increase in the MS of 32.6% compared to 13.1% by the RT. Significant MCTT-induced MS increase was observed during the second menstrual cycle. The ratio of MS/MCA increased by 10.5% (RT) and 27.6% (MCTT). Despite a wide interindividual variability, all subjects showed higher strength adaptations by MCTT. Additionally, we found significant correlations between different force parameters and the accumulation of estradiol. It was concluded that the MCTT seems to be more efficient compared to RT.