Should women get different sport and exercise science advice/support than men? The honest answer is that [right now] we just don’t know. We speculate that, due to the numerous anatomical, physiological and psychological difference between men and women, different ‘sex-based’ guidance is needed.
Differences between men and women
One of the biggest differences between men and women is reproductive physiology/endocrinology; following puberty men have relatively stable sex hormone levels, whilst adult women have:
Cyclical changes in ovarian hormones (i.e., menstrual cycle)
Commonly ingest synthetic steroid hormones (i.e., hormonal contraceptives)
Can encounter supraphysiological levels of oestrogen and progesterone (i.e., pregnancy), before experiencing a rapid decline in ovarian hormone concentrations (i.e., menopause).
These dynamic changes in reproductive hormone profiles underpin studies investigating sex differences, as well as studies investigating the effects of menstrual cycle phase, hormonal contraceptive use, pregnancy and the menopause on aspects of nutrition, training, performance and health.
"More research is needed..."
Unfortunately, [right now] nearly all studies, in sport and exercise science with women as participants, end with “…more research is needed…”. What they should say is that “…more high-quality research is needed…”. Alongside the current shortage of female-specific data, is a lack of high-quality data, which can largely be attributed to (i) vague participant selection criteria and (ii) inadequate experimental designs.
Who is being studied?
Specifically this relates to the poor definition, selection and confirmation of the sampled population. For example, in the past, researchers have assumed eumenorrheic status, based purely on the presence of menstruation. In reality, menstruation can occur in anovulatory (i.e., a cycle where ovulation does not occur) and luteal phase deficient (i.e., a cycle with reduced mid-luteal phase progesterone levels) cycles, neither of which should be described as a eumenorrheic cycle.
There is a lack of high-quality data, which can largely be attributed to (i) vague participant selection criteria and (ii) inadequate experimental designs
Moreover, a spotlight has been placed on the menstrual cycle in sport and exercise science studies, when, in truth, the menstrual cycle only accounts for a portion [not the majority] of women. Moving forwards, we need to consider:
Hormonal contraceptive users [not just oral contraceptive pill users]
Women with menstrual irregularities (e.g., amenorrhea, oligomenorrhea)
Hormone replacement therapy users
Each of these groups of women represent different ovarian hormonal profiles (i.e., they have different amounts of oestrogen and progesterone). Evidently, ‘women’ are not all the same. As such, we need clear, universal definitions for each ovarian-based hormonal profile associated with women across the lifespan. By having these [a priori] definitions, which we retrospectively [a posteriori] confirm, we can have confidence that the sampled population accurately represents the intended ‘type/category’ of woman.
With regards to experimental design, studies involving women as participants need to particularly consider:
The timeframe (e.g., tracking menstrual cycle characteristics for ≥ 2 months prior to the commencement of the study) and procedures (e.g., blood sample determination of oestrogen and progesterone to identify/confirm a specific phase of the menstrual cycle) needed
The number of times a participant needs to be tested/assessed (e.g., two, three, four… phases of the menstrual cycle) and the timing of those sessions (e.g., during menstruation, in the 24 preceding or following confirmation of ovulation, + 7 days following the confirmation of ovulation) in order to represent their ovarian hormonal profile
The inter and intra-individual variability in ovarian hormone profiles (e.g., eumenorrheic cycle length can vary between 21 and 35 days) and how to deal with this variability (e.g., using only one brand/type of oral contraceptive pills to reduce the variability in endogenous oestrogen concentrations). This means that the experimental design of studies with women as participants needs to be adapted in response to the ovarian hormonal status of the participants (e.g., consideration of menstrual cycle phase, type of hormonal contraceptive used, stage of menopause).
By carefully and consistently considering the sample characteristics and adapting the research design to reflect female specific criteria, sport and exercise scientists will be able to: (i) generate meaningful female-specific data; (ii) close the sex data gap; and (iii) support [sports]women to achieve their full [sporting] potential on any given day regardless of reproductive status.
*Pubertal, pregnant and menopausal participants exist along a hormonal continuum; i.e., different hormone concentrations between pre, during and post time-points.
Elliott-Sale KJ, Minahan CL, de Jonge XAKJ, Ackerman KE, Sipilä S, Constantini NW, Lebrun CM, Hackney AC. Methodological Considerations for Studies in Sport and Exercise Science with Women as Participants: A Working Guide for Standards of Practice for Research on Women. Sports Med. 2021 Mar 16. doi: 10.1007/s40279-021-01435-8. Epub ahead of print.