Due to ethical reasons, accurate measurements of prenatal testosterone exposure in humans are difficult, and a limited number of studies have been conducted in this area to date. The ‘Organisational hypothesis’ suggests that prenatal sex steroids, particularly testosterone, modify growth and development in a sexually dimorphic way 3. Hence, the 2D:4D ratio in adults may partly reflect neonatal testosterone exposure, along with prenatal exposure 1, 2. It is hypothesised that sexual dimorphism in the 2D:4D ratio is a product of the cumulative effects of both prenatal and postnatal developmental processes 1. recently strengthened opposition against the use of the 2D:4D ratio, partly based on the idea that the 2D:4D ratio is a mere artifact of the allometric effects of digit growth. the high popularity of the 2D:4D ratio used for testing different traits related to androgenisation and estragenisation during critical periods of prenatal development and 2. The idea for this study stemmed from two facts: 1. We conclude that sex differences in 2D:4D are not an artifact of allometry. No allometric effect was observed in this case. Height was applied as another measure of allometric effect on the limited sample (≤ 30 years) from the European population, along with sex and age. Both sex and population origin were permanent reliable predictors of 2D:4D, whereas average digit length was not. To test for an allometric effect on 2D:4D, the average digit lengths were calculated. However, the 2D:4D magnitude and its sexual dimorphism remained stable throughout the ontogeny. The second and fourth digits showed strong positive linear relationships on both hands, and demonstrated an increase with age digit length in women from the youngest age cohort was longer or equal to that of men, and shorter than men in older age cohorts. Additionally, we separately tested four age cohorts (≤ 13, 14–18, 19–30, and 31 ≥ years) to test the effect of developmental allometry. Analyses were conducted separately for each hand for the whole sample and in succession for the three large populations. Digit ratios were computed according to standard procedures. The lengths of the second and fourth digits on both hands were measured. The study sample comprised 7,582 individuals (3,802 men and 3,780 women) from three large world populations: Europeans (n = 3043), East Africans (n = 2844), and Central Asians (n = 1695). The goal of our study is to verify the validity of these assumptions. We discuss the effect sizes for relationships between 2D:4D and sport and target traits in general, and identify areas of strength and weakness in digit ratio research.Recently, a number of authors have claimed that sexual dimorphism in the second-to-fourth digit ratio (2D:4D) is simply dependent on digit length and is an artifact of allometry. This suggests that 2D:4D is a relatively weak predictor of strength and a stronger predictor of efficiency in aerobic exercise. However, associations between 2D:4D and sprinting speed were much weaker than those reported for endurance running. The relationship was also found for 50 m split times (at 20, 30, and 40 m) and was independent of age, BMI, and an index of maturity. runners with low 2D:4D ran faster than runners with high 2D:4D). Here we show that running times over 50 m were positively correlated with 2D:4D in a sample of 241 boys (i.e. Speed in endurance races is strongly related to 2D:4D, and may be one factor that underlies the link between sport and 2D:4D, but nothing is known of the relationship between 2D:4D and sprinting speed. Digit ratio (2D:4D), a putative correlate of prenatal testosterone, has been found to relate to performance in sport and athletics such that low 2D:4D (high prenatal testosterone) correlates with high performance.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |