OMG I had a big post and it deleted it because of the less-than-sign bug!
Here's the abstract:
Objective To describe and characterise serum androgen levels and to study their possible influence on athletic performance in male and female elite athletes. Methods 2127 observations of competition best performances and mass spectrometry-measured serum androgen concentrations, obtained during the 2011 and 2013 International Association of Athletics Federations World Championships, were analysed in male and female elite track and field athletes. To test the influence of serum androgen levels on performance, male and female athletes were classified in tertiles according to their free testosterone (fT) concentration and the best competition results achieved in the highest and lowest fT tertiles were then compared.
Results The type of athletic event did not influence
fT concentration among elite women, whereas male sprinters showed higher values for fT than male athletes in other events. Men involved in all throwing events showed significantly (p less than 0.05) lower testosterone and sex hormone binding globulin than men in other events. When compared with the lowest female fT tertile, women with the highest fT tertile performed significantly (p less than 0.05) better in 400 m, 400 m hurdles, 800 m, hammer throw, and pole vault with margins of 2.73%, 2.78%, 1.78%, 4.53%, and 2.94%, respectively. Such a pattern was not found in any of the male athletic events. Conclusion Female athletes with high fT levels have a significant competitive advantage over those with low fT in 400 m, 400 m hurdles, 800 m, hammer throw, and pole vault.
Of particular interest, they studied 1332 elite female athletes, and:
"Twenty-four female athletes showed a T concentration [morethan] 3.08nmol/L which has been calculated to represent the 99th percentile in a previous normative study in elite female athletes. 13 Among these 24 individuals, nine were diagnosed with a condition of hyperandrogenic disorder of sex development (DSD), nine were later found to have been doping, and six athletes were impossible to classify."
"In order to test the influence of serum androgen levels on athletic performance, in each of the 21 female athletic events and 22 male athletic events, athletes were classified in tertiles according to their fT concentration. Then, the athletic performances and Hb concentrations of the highest and lowest fT tertiles were compared by using non-paired Student's t-test. These different athletic events were considered as distinct independent analyses and adjustment for multiple comparisons was not required."
There are several problems here:
1. The last line is completely wrong. They deliberately didn't account for multiple testing corrections. They're wrong for doing this. You ALWAYS have to account for multiple testing correction. They tested 43 events. If there is NO effect, you expect 2 of them (on average -- it could be 0 or 4) to test significant at the p less than 0.05 level. This is the definition of the p-value. They only found 5 positives. None of their p values were below 0.01. If they perform multiple testing corrections they wouldn't have any significant results. What if they tested 100 events and found 5 significant, would they still be significant? Come on. My officemate is laughing at me as I tell him this.
2. The data isn't normally distributed (times aren't normally distributed), but this is a minor point. It can skew the results a little.
3. The sprint results are funny. For the 100m, 100mH, 200m, the athletes with HIGHER testosterone levels ran SLOWER times! For the 100m, the effect is even bigger than the 800m, and there are more subjects in the 100m! I guess they didn't report it as "significant" because they were looking for things in the opposite direction (probably to get smaller p-values). Those masking agents!
4. They included DSD athletes in the study. Keeping in Semenya and Niyonsaba skews the results towards higher testosterone and lower times. With 64 athletes in the 800m, there are 21 in the upper tertile, so the results of 2 athletes could have a big effect on the results.
I gotta go. Shame my longer post was deleted.