Endocrine Abstracts

Athletic performance is influenced by the interaction of biological, environmental and psychological factors. Among biological factors, endocrine function is particularly important, with sex steroid hormones influential in the regulation of muscle protein synthesis, erythropoiesis and skeletal development, all of which influence phenotypes directly relevant to athletic performance. Variation in hormone exposure, androgen sensitivity and developmental timing contribute to observed differences in muscle mass, haemoglobin concentration and cardiopulmonary capacity. Indeed, it is sustained differences in androgen exposure during puberty that are associated with the typical sex-related divergence observed in key athletic phenotypes such as strength, power and endurance. Differences of sex development (DSD), however, encompass a range of distinct biological variations in which chromosomal, gonadal and hormonal characteristics may not align with typical developmental patterns. Consequently, the impact of these sex variations on biological phenotypes relevant to athletic performance is less clearly defined. In sport, athlete classification has typically relied on biological markers intended to reflect relevant physiological characteristics, including circulating testosterone concentrations and, more recently, the presence of Y chromosome material. Such markers, however, do not account for variation in receptor function or developmental history, limiting their ability to fully capture the biological diversity observed in athletes with DSD and their relationship to performance. While evidence directly linking DSD-related biology to athletic performance remains limited, emerging performance analyses from elite sport suggest that outcomes among athletes subject to DSD-related regulations are variable and generally fall within the range observed in the women’s sport category, without clear separation from elite female performance. Together, these findings emphasise the need to interpret biological markers within the broader context of athletic performance when considering DSD in sport.