The effect of acute caffeine consumption on strength and muscle endurance in resistant exercise with different intensity in trained men

The aim of this study was to determine, the effect of acute consumption of caffeine on maximum strength, muscle endurance (number of repetitions to exhaustion) and the blood lactate in the two different intensity of resistance exercise in trained men. Sixteen bodybuilders (mean age 7.3±50.25 years, Height 27.5 ± 37.177 cm and weight 14.2±5.87 kg) were selected. In the first session the participants performed one repetition maximum­­ (1RM) test after taking placebo capsules, while in the second session they took capsules which contained caffeine (6 mg/kg). In the third session, the participants took placebo capsules and performed repetitions to exhaustion in two tests with 60% 1RM. The levels of blood lactate were immediately measured at this point. In the fourth session, they took caffeine and the same protocol of the third session was executed. In the fifth session, placebo was introduced and the participants performed repetition to exhaustion for the two testes with 80% 1RM and then lactate levels of blood were measured. The next session entailed taking caffeine and the participants did the previous session protocol. The results of independent-samples T-test analysis (P=0.05) showed that caffeine consumption, as compared to placebo, significantly affected the number of repetition to exhaustion with 60% intensity 1RM in leg press item, while there was no significant change in other variables. Consequently, it seems that acute caffeine consumption has increased the number of repetition to exhaustion in low intensity particularly for lower body movements.