The athletic status is a composite multi-factorial output. Sprinting success can be pinned purely on nature and nurture. Along with societal factors investment in infrastructure, training system and powerful desire play an important role. The evolutionary advantage in the form of ACTN3, gene for speed, the physiological determinant of the sprinting ability has come into main focus recently. Most studies have demonstrated a relationship between the presence of Alpha actin3 and the ability of muscle to generate force. The aim of our study was to analyse the various physiological factors contributing to the power performance of adolescent swimmers. The study assessed their socio-economic status, anthropometric measurements, pulmonary function tests and ACTN3 genotype. This was a case control study. The cases being 35 in number and age matched controls, 70 in number. Human ethical committee clearance was obtained. The subjects were chosen from different swimming pools in Chennai, Tamilnadu, India. All members were briefed about the intent and conduct of tests. The volunteers were then chosen in strict adherence to the inclusion and exclusion criteria. Informed consent was obtained from the participant and Anthropometric measurements were recorded. After demonstration of proper technique Spirometry was done. ACTN3 gene testing was done from cheek swabs. The results were statistically analysed using Graph Pad Prism- version 5. The mid-arm circumferences of swimmers and controls were compared. Unpaired ‘t’ test was applied. The P value was 0.002. The means were significantly different, P<0.05. Fisher’s test was performed and variances compared. The P value was 0.0224. The proportion test of ACTN3 genotype was done. It was inferred that RR type and RX type difference in proportion between cases and controls was not significant but XX type proportion was significant between groups. On analysis of results we concluded that swimmers had better anthropometric measurements. Their Spirometry revealed better values. The ACTN3 genotyping showed R allele was associated with elite swimming performance.