STRENGTH EXPRESSION IN FEMALE ATHLETES; DOES THE MENSTRUAL CYCLE REALLY MATTER?

The relationship between the menstrual cycle and various markers of health is complex and variable, influenced by the ever-changing associated hormonal profile. Female athletes have reported negative impacts on daily life and training as a result of their menstrual cycle, such as abdominal and back pain to migraines, which can result in missed training sessions or needing to alter training sessions. It is important to understand how the unique physiology of female athletes influences their ability to perform, and with only 35-37% of sports science research participants being female, it is imperative to increase representation of female participants in sport science research. This study investigates the effect of menstrual cycle phase on maximal strength across team sport athletes. Eumenorrheic female athletes (N=10, age; 25.3 ± 4.5yrs, weight; 70.2 ± 11.6kg) undertook maximal isometric squat testing three times per week for one complete menstrual cycle after reporting two months of consistent menstrual cycle activity. Absolute and relative maximal strength and rate of force development were analysed at each phase of the menstrual cycle as a group. Data were also assessed individually to identify participants with similar trends in their strength profile across the menstrual cycle, resulting in three individual groups. As a collective, there were no significant differences in maximal strength characteristics across the menstrual cycle phases tested. There were significant differences (P<0.05) in absolute peak force (APF) and relative peak force (RPF) between Menstrual Phase (MP) and Follicular Phase (FP), MP and Luteal Phase (LP), Ovulation (OV) and LP in Individual Group One with reduced peak force in FP (10.5% APF, 7.7% RPF), LP (13.5%, 13%), and OP (10%, 11.8%) respectively. There were significant differences in Individual Group Two between FP and OP, and FP and LP for APF and RPF with decreased peak force in FP for both comparisons (12.6%, 12.4% & 15.2%, 18.3%). Data for APF in each phase of the menstrual cycle for each participant can be seen in Figure 1. Considering the menstrual cycle can affect individuals differently, assessing menstrual cycle data collectively may be a disservice to the female athlete and prohibits further understanding of how individual athletes are impacted across the various menstrual cycle phases. Thus, assessing data individually or grouping data sets with similar patterns may provide more nuanced information about the influence of menstrual cycle phase on strength characteristics, which could have implications for athletes’ training. Further research is needed, however the results from this study highlight that an individual athlete’s maximal strength may vary on an individual bases during the different phases of the menstrual cycle. It is recommended female athletes monitor fluctuations in strength across different phases of the menstrual cycle to see how each phase may alter strength expression. [ABSTRACT FROM AUTHOR]