In order to excel in sport, apart from the correct training, the genetic combination of an individual
may also be a factor in making an elite athlete. Weightlifting, as a popular sport, has a unique biomechanism
dealing with muscle performance. The current study investigated the polymorphisms of the
angiotensin-converting enzyme (ACE), the -actinin-3 (ACTN3), and the vitamin D receptor (VDR)
genes (individually or in combination) in Thai weightlifters. A total of 117 male and female national and
junior Thai weightlifters, and 99 healthy sedentary people were recruited for this study. Genotyping was
analyzed by Polymerase Chain Reaction (PCR) and Polymerase Chain Reaction - Restriction Fragment
Length Polymorphism (PCR-RFLP). When compared to the junior and non-athletes group, the genotype
and allele frequencies of ACE (DD), ACTN3 (RR), and VDR (ff) were more frequent in both male and
female national weightlifters. In addition, the genotype combinations between ACE (DD) + VDR (ff),
ACE (DD) + ACTN3 RR, and ACTN3 RR + VDR ff presented highly in both genders of national
weightlifters. Taken together, our results suggest that the ACTN3 and VDR genotype, individually or in
combination, may influence muscle performance in weightlifters, appearing to significantly contribute to
better weightlifting performance.