In creating a threshold for eligibility for female events it is also necessary to make allowance for women with polycystic ovary syndrome (PCOS) and nonclassical adrenal hyperplasia. A reliable threshold for circulating testosterone must be set using measurement by the reference method of liquid chromatography–mass spectrometry (LC-MS) rather than using one of the various available commercial testosterone immunoassays. Unsurprisingly, this dilemma has always been highly contentious since it first entered international elite sports in the early 20th century, and it has become increasingly prominent and contentious in recent decades; nevertheless, the requirement to maintain fair play in female events will not disappear as long as separate female competitions exist. Prior to puberty, levels of circulating testosterone as determined by LC-MS are the same in boys and girls (16). Only when circulating testosterone concentrations rise in male adolescents above the prepubertal concentrations does the virilization characteristic of men commence, progress, and endure throughout adult life, at least until old age (18). After birth and until puberty commences, circulating testosterone concentrations are essentially the same in boys and girls, other than briefly in the neonatal period of boys when higher levels prevail. The two dominant bioactive androgens circulating in mature mammals, including humans—testosterone and its more potent metabolite DHT—account for the development and maintenance of all androgen-dependent characteristics, and their circulating levels in men and nonpregnant women arise from steroids synthesized de novo in the testes, ovary, or adrenals (12). Excellent, insightful discussion of the legal and moral complexities of sex and fair competition in elite sports from a legal scholar and former elite female athlete is available (2). All scored waves were completed within 25 min of getting into the wave pool. All scored waves were completed within 25 min of getting into the wave pool.Data were first assessed to establish whether they met the assumptions of parametric statistical analysis (i.e., the Shapiro–Wilk test for normality and Levene's test of equality). The water temperature in the wave pool was a consistent 13–16°C each session. Among the nonhormonal factors, genetics explains a large proportion ∼50% to 60% from pooled twin studies (156) of the variability in muscle mass and strength (157, 158) and may be explained in turn by the equally high genetic contributions to circulating testosterone (37, 38). Many if not most other aspects of physiology exhibit sex differences and may therefore enhance the impact of the male advantage in sports performance of the dominant determinants (muscle and hemoglobin). Conversely, one prospective 12-month study of transgender (nonathlete) individuals reported that testosterone suppression (by an estrogen-based regimen) to normal female levels in 20 (M2F) transwomen reduced hemoglobin by 14%. Similarly, two prospective studies of the first 12 months of treatment of transmen female-to-male (F2M) transgender shows a consistent major increase in muscle mass and strength due to testosterone administration. Studies of the ergogenic effects of supraphysiological concentrations of circulating testosterone require studies administering graded doses of exogenous testosterone for months. A novel finding from this present study was that the gain in thermal properties mirrored performance improvement across waves, and the advantage lasted at least 25 min in the water; given the small number of participants, this was a strong finding. In fact, other sports studies, in which an appropriate warm-up has been explored, have produced quite compelling evidence that has been instrumental in forwarding an argument for warm-ups and understanding the effect of thermal profiles on surfing performance (36). Median scores given to participants for the first set of waves and second set of waves and an overall score (i.e., the score for both sets of waves combined) under warm-up conditions and control conditions. The core body temperatures in degrees Celsius of participants during the warm-up (or control) and surfing session. Again, the assumption were not met; therefore, a Friedman's test was performed on all the data combined, on male only data, and on female only data to establish whether a difference existed between sessions and within sessions for testosterone, cortisol, and the testosterone-to-cortisol ratio. These assumptions were not met by all data; as such, a Friedman's test was performed on all data combined, on male only data, and on female only data to establish whether a difference existed between sessions and within sessions for core body temperature. Furthermore, there is evidence that the androgen sensitivity of responsive tissues differs and may be optimal at different circulating testosterone concentrations (65). However, these latter pattern effects are subtle and the dominant effect remains that of dose and average testosterone concentrations in blood, however they arise. Any purported differences between endogenous and exogenous testosterone are due to corresponding differences in the endogenous production rate or exogenous dose. The pooled data reveal that the upper limit of serum testosterone in women with PCOS is 3.1 nmol/L (95% CI, one-sided) or 4.8 nmol/L (using a 99.99% CI, one-sided) (Table 3). PCOS is a relatively common disorder among women of reproductive ages with a prevalence of 6% to 10%, depending on the diagnostic criteria used (44), in which mild hyperandrogenism is a key clinical feature and has higher than expected prevalence among elite female athletes (36, 45–47).
