The effect of CYP1A2 genotype on the ergogenic properties of caffeine during resistance exercise: a randomized, double-blind, placebo-controlled, crossover study
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The purpose of this study was to examine the effect of CYP1A2 -163C>A polymorphism on the ergogenic effects of caffeine supplementation during a resistance exercise (RE) session.
In a randomized, double-blind, placebo (PL)-controlled, crossover study, 30 resistance-trained men took part in two RE sessions (three sets to failure at 85% of one repetition maximum, 2-min rest between sets), including bench press (BP), leg press (LP), seated cable row, and shoulder press (SP) following caffeine (CAF) (6 mg kg−1) or PL (6 mg kg−1 of maltodextrin) ingestion 1 h prior to the trial. The number of repetitions was recorded after each set, along with calculation of total number of repetitions for each exercise. Genomic DNA was isolated from the whole blood samples for analyzing the CYP1A2 -163C>A polymorphism through amplification refractory mutation system–polymerase chain reaction (ARMS–PCR). Subjects were classified as either AA (n = 14) or AC/CC genotypes (n = 16).
The two-way ANOVA with repeated measures revealed differences between AAs and AC/CCs under CAF conditions for repetitions performed in sets 1, 2, and 3 of BP (F(1, 28) = 14.84, P = 0.001, ƞ2 = 0.34), LP (F(1, 28) = 8.92, P = 0.006, ƞ2 = 0.24), SR (F(1, 28) = 17.38, P = 0.0001, ƞ2 = 0.38), and SP (F(1, 28) = 3.76, P = 0.063, ƞ2 = 0.11). CAF also increased the total number of repetitions performed for all three sets in AAs versus AC/CCs for BP (F(1, 28) = 8.72, P = 0.006, ƞ2 = 0.23), LP (F(1, 28) = 4.67, P = 0.03, ƞ2 = 0.14), SR (F(1, 28) = 5.54, P = 0.02, ƞ2 = 0.16), and SP (F(1, 28) = 3.89, P = 0.058, ƞ2 = 0.12) in athletes who were homozygous carriers of the A allele, compared to the C allele carriers. Therefore, AA homozygotes were able to carry out a greater total volume of RE work under CAF but not PL conditions, compared to the C allele carriers.
In conclusion, acute ingestion of CAF significantly enhanced RE performance in resistance-trained men who were homozygous for the A allele, but not for C allele carriers. Further studies are needed to replicate the potential role of the CYP1A2 -163C>A polymorphism on the ergogenic effects of CAF in other modes of exercise and in other populations.
KeywordsCaffeine CYP1A2 -163C>A polymorphism Resistance exercise
The author wishes to thank the subjects who volunteered for the study.
This research project was funded by the University of Kurdistan (grant number 14/20137; Monday, 13 July 2015).
Compliance with ethical standards
All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards.
Conflict of interest
The author declares that there is no conflict of interest.
Informed consent was obtained from all individual participants included in the study.
- 6.Beck TW, Housh TJ, Schmidt RJ, Johnson GO, Housh DJ, Coburn JW, Malek MH (2006) The acute effects of a caffeine-containing supplement on strength, muscular endurance, and anaerobic capabilities. J Strength Cond Res 20(3):506–510Google Scholar
- 10.Wong K, Martin B, Volland L, Rohmann R, Astorino T (2008) Effect of caffeine ingestion on resistance training performance. In: Southwest ACSM MeetingGoogle Scholar
- 15.Shimada T, Yamazaki H, Mimura M, Inui Y, Guengerich FP (1994) Interindividual variations in human liver cytochrome P-450 enzymes involved in the oxidation of drugs, carcinogens and toxic chemicals: studies with liver microsomes of 30 Japanese and 30 Caucasians. J Pharmacol Exp Ther 270(1):414–423Google Scholar
- 24.Baechle TR, Earle RW (2008) Essentials of strength and conditioning. In: Baechle TR, Earle RW (eds) Resistance training and spotting techniquesGoogle Scholar
- 25.Medrano RFV, de Oliveira CA (2014) Guidelines for the tetra-primer ARMS–PCR technique development. Mol Biotechnol 56(7):599–608Google Scholar
- 32.Davis J, Zhao Z, Stock HS, Mehl KA, Buggy J, Hand GA (2003) Central nervous system effects of caffeine and adenosine on fatigue. Am J Phys Regul Integr Comp Phys 284(2):R399–R404Google Scholar
- 36.Karcz-Kubicha M, Antoniou K, Terasmaa A, Quarta D, Solinas M, Justinova Z, Pezzola A, Reggio R, Müller CE, Fuxe K (2003) Involvement of adenosine A1 and A2A receptors in the motor effects of caffeine after its acute and chronic administration. Neuropsychopharmacology 28(7):1281–1291CrossRefGoogle Scholar