We have previously demonstrated that, ACE D allele may be related with a better performance in short duration aerobic endurance in a homogeneous cohort with similar training backgrounds. We aimed to study the variation in the short-duration aerobic performance development amongst ACE genotypes in response to identical training programs in homogeneous populations. The study group consisted of 186 male Caucasian non-elite Turkish army recruits. All subjects had undergone an identical training program with double training session per day and 6 days a week for 6 months. Performances for middle distance runs (2,400 m) were evaluated on an athletics track before and after the training period. ACE gene polymorphisms were studied by PCR analysis. The distribution of genotypes in the whole group was 16.7% II, n = 31; 46.2% ID, n = 86; 37.1% DD, n = 69. Subjects with ACE DD genotype had significantly higher enhancement than the ID (P < 0.01) and II (P < 0.05) genotype groups. Around 2,400 m performance enhancement ratios showed a linear trend as ACE DD > ACE ID > ACE II (P value for Pearson chi(2) = 0.461 and P value for linear by linear association = 0.001). ACE DD genotype seems to have an advantage in development in short-duration aerobic performance. This data in unison with the data that we have obtained from homogenous cohorts previously is considered as an existence of threshold for initiation of ACE I allele effectiveness in endurance performance. This threshold may be anywhere between 10 and 30 min with lasting maximal exercises.