Resumo Os métodos contraceptivos hormonais são usados por aproximadamente metade das atletas do sexo feminino e podem afetar o desempenho atlético como resultado de sua ação hormonal sistêmica. Nas atletas, o uso de anticoncepcionais parece ter pouco efeito sobre a composição corporal, porém novos estudos são necessários para avaliar os efeitos dos contraceptivos derivados apenas de progestina, pois podem ter um efeito negativo na população em geral. O tipo de progestina contido dentro do contraceptivo pode influenciar a resposta anabólica do músculo, embora esta relação seja complexa em virtude dos efeitos diretos ou indiretos de hormônios exógenos na síntese da proteína e na proliferação das células satélites. A resposta sistêmica hormonal alterada em usuárias de contraceptivos parece não influenciar a força muscular e, embora o consumo máximo de oxigênio às vezes seja reduzida, isso não afeta as medidas de desempenho. A maioria das pesquisas utilizou desenhos transversais e/ou agrupou diferentes tipos e marcas de anticoncepcionais hormonais e poucos estudos têm sido realizada sobre anticoncepcionais com progestina em atletas. Futuros estudos devem usar desenhos experimentais prospectivos, randomizados e controlados para avaliar os efeitos de todos os tipos de contraceptivos hormonais no desempenho atlético em mulheres.

Abstract Hormonal contraceptives are used by approximately half of female athletes and may affect athletic performance as a result of their action on the endogenous hormonal milieu. In athletes, hormonal contraceptive use appears to have little effect on body composition, however further studies are needed assessing progestin-only contraceptives as they may have a negative effect in the general population. The type of progestin contained within the contraceptive may influence the anabolic response of muscle to loading although this relationship is complex as it may be due to either direct or indirect effects of exogenous hormones on protein synthesis and satellite cell proliferation. The altered hormonal milieu in hormonal contraceptive users has predominately been shown to have no effect on muscle strength and whilst maximal oxygen uptake is sometimes reduced, this does not translate into measures of performance. The majority of previous research has used cross-sectional designs and/or grouped together different types and brands of hormonal contraceptives and little research has been conducted on progestin-only contraceptives in athletes. Future research should use prospective, randomised-controlled designs to assess the effects of all types of hormonal contraceptives on athletic performance in females.

The relationship between muscle strength and oestrogen is ambiguous and is still largely unresolved. The evidence for and against an effect of oestradiol on determinants of muscle function is equivocal and often contradictory. The bulk of the research in this area was performed during the eighties and nineties, using models of reproductive functioning such as; the menstrual cycle, the menopause and hormone replacement therapy, oral contraceptives and in vitro fertilisation treatment, to alter the female hormonal milieu. In the last decade, approximately 15 papers have demonstrated a relationship, both positive and negative, between the concentration of oestrogen and skeletal muscle strength. Conversely, around 20 articles have not shown any influence of oestrogen on a number of strength measures. The majority of these studies were performed using post-menopausal and eumenorrheic females. Most current studies use hormonal assays to confirm oestrogen status, however no recent studies have reported the bioavailable concentration of oestradiol. Similarly, no research in the last 10 years has used in vitro fertilisation treatment or pregnancy as acute and chronic models of supra-physiological changes in sex hormone concentration. Future work should focus on performing meta-analyses on each of the key components of muscle strength in an attempt to elucidate a causal relationship. In addition, models of reproductive functioning that cause the greatest magnitude of change to oestrogen concentration should be used, while controlling as many confounding factors as possible.