Influence of Menstrual Cycle and Oral Contraceptive Phases on Strength Performance, Neuromuscular Fatigue and Perceived Exertion

The aim of the study was to assess differences in strength performance, neuromuscular fatigue and perceived exertion across phases of the menstrual cycle (MC, early follicular [eFP], late follicular [lFP] and mid-luteal phase [mLP]) and oral contraceptives (OC, active pill phase [aPP] and non-active pill phase [nPP]). Secondly, in naturally menstruating women, the influence of fluctuating serum 17β-estradiol nd progesterone concentrations on these parameters were analysed. Thirty-four women (21 with a natural MC and 13 using OCs) completed three or two experimental sessions, respectively. Mean mean propulsive velocity (MPVmean) and total number of repetitions (REPtotal) were assessed during a power (3x8 at 60%1RM) and hypertrophy squat loading (3 sets to failure at 70%1RM), respectively. Change in bench press and squat MPV at 60%1RM in response to the loadings were used as surrogates for non-local and local fatigue, respectively. Total blood lactate accumulation (BLAA) and markers of perceived exertion were assessed in each session. No significant differences between any of the MC or OC phases were observed for MPVmean, REPtotal, non-local and local fatigue and markers of perceived exertion (all p>0.050). A higher intraindividual 17β-estradiol concentration was significantly associated with a lower MPVmean (p=0.019). BLAA was significantly higher in lFP compared to mLP (p=0.019) and negatively associated with the intraindividual progesterone concentration (p=0.005). While 17β-estradiol may negatively influence the MPV, it appears that fluctuations of both sex hormones across the MC and OC phases are not prominent enough to induce significant nor practically relevant changes in the assessed parameters.