The five steps that were followed in the statistical analysis. MARS: Multivariate Adaptive Regression Splines, BIF: Bootstrap Inclusion Fraction. Firstly, we selected the best genetic model for each SNP by testing three inheritance models (dominant, recessive and additive model) for each SNP in the entire cohort of sprint/power athletes. Secondly, MARS was used to detect SNP main effects and SNP-SNP interactions (rs1867785 and rs11689011 were used in two independent MARS models because of their strong linkage disequilibrium). Thirdly, the covariates selected by MARS were input into a logistic regression model to determine their significance, and all covariates with p-value > 0.05 were excluded. Fourthly, to validate the selected covariates, we repeated steps 2 and 3 on 10000 random samples with replacement from the original dataset and calculated the how many times the selected covariates were significant in the 10000 random samples (BIF). All covariates with a BIF < 50% were excluded. Fifthly, we calculated the odds ratio of the genotype combinations for each selected covariate to give a clear biological interpretation.