engleski

Acute Enhancement of Jump Performance, Muscle Strength, and Power in Resistance-Trained Men After Consumption of Caffeinated Chewing Gum

To explore the acute effects of caffeinated chewing gum on: (1) vertical jump performance ; (2) isokinetic knee extension/flexion strength and power ; (3) barbell velocity in resistance exercise ; and (4) whole-body power. METHODS: Nineteen resistance-trained men consumed, in randomized counterbalanced order, either caffeinated chewing gum (300 mg of caffeine) or placebo, and completed exercise testing that included squat jump (SJ), countermovement jump (CMJ), isokinetic knee extension and knee flexion at angular velocities of 60°·s-1 and 180°·s-1, bench press exercise with loads corresponding to 50%, 75%, and 90% of one repetition maximum (1RM), and an "all-out" rowing- ergometer test. RESULTS: Compared to placebo, caffeinated chewing gum enhanced (all P<0.05): (1) vertical jump height in the SJ (effect size [ES]=0.21 ; +3.7%) and CMJ (ES=0.27 ; +4.6%) ; (2) knee extension peak torque (ES=0.21 ; +3.6%) and average power (ES=0.25 ; +4.5%) at 60°·s-1 and knee extension average power (ES=0.30 ; +5.2%) at 180°·s-1 ; knee flexion peak torque at 60°·s-1 (ES=0.22 ; +4.1%) and 180°·s-1 (ES=0.31 ; +5.9%) ; (3) barbell velocity at 50% of 1RM (ES=0.30 ; +3.2%), 75% of 1RM (ES=0.44 ; +5.7%), and 90% of 1RM (ES=0.43 ; +9.1%) ; and (4) whole-body peak power on the rowing- ergometer test (ES=0.41 ; +5.0%). Average power of the knee flexors did not change at neither angular velocity with caffeine consumption. CONCLUSIONS: Caffeinated chewing gum with a dose of caffeine of 300 mg, consumed 10 minutes pre-exercise, may acutely enhance vertical jump height, isokinetic strength and power of the lower-body musculature, barbell velocity in the bench press exercise with moderate to high loads, and whole-body power.

caffeine ; ergogenic aid ; exercise performance ; resistance training

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