Author(s): MONTALVO ALONSO, J., DEL-VAL MANZANO, M., FERRAGUT, C., VALADÉS, D., PÉREZ-LÓPEZ, A., Institution: UNIVERSIDAD DE ALCALÁ, Country: SPAIN, Abstract-ID: 2536

INTRODUCTION:
Numerous studies have demonstrated the ergogenic effect of acute caffeine intake in different
sports actions. In resistance exercise, caffeine enhances velocity and power production at
different loads and exercise types (e.g., bench press or back squat). However, it remains unclear
whether the acute ergogenic effects of this supplement can accumulate over consecutive
exercise sessions, specifically if prolonged caffeine intake before resistance exercise enhances
neuromuscular adaptations. Therefore, this study aimed to evaluate the effect of pre-exercise
caffeine intake during 8-weeks of velocity-based resistance training.
METHODS:
Forty-eight resistance-trained participants (male/female: 24/24; age: 24±4 years; training
experience: 3.8±3.3 years; 1RM/kg bench press: 1.1±0.3; 1RM/kg back squat: 1.6±0.6;
caffeine intake: 50.5±50.9 mg/day) participated in a double-blind, randomized, placebo-
controlled trial. Participants completed an 8-week, twice-weekly velocity-based resistance
training for bench press and back squat exercises at progressive loads (70-85%1RM). Four sets
were performed per exercise until a 20% velocity loss occurred. Sixty minutes pre-exercise,
they ingested 3 mg/kg of caffeine or placebo. Pre- and post-training tests included 1RM,
muscular strength and power tests at 25%, 50%, 75%, 90% 1RM, and muscular endurance at
65% 1RM performing one set until task failure. Movement velocity was monitored in all cases.
Moreover, acute caffeine effects were assessed before and after the intervention.
RESULTS:
Resistance training significantly increased 1RM in both bench press and back squat (13-19%,
P<0.001), with caffeine supplementation resulting in greater improvements than placebo in
bench press for both sexes (5.5%, P=0.043) and in back squat specifically for females
compared to males (8% vs 2%, P=0.021). In bench press at 25% and 50%1RM, caffeine
increased mean velocity (7% vs 14%, P=0.050; 0.5% vs 9%, P=0.010) and mean power (17%
vs 38%, P=0.047; 12% vs 20%, P=0.041) compared to placebo. In back squat at 25%, 50% and
75%1RM, caffeine increased mean velocity (3% vs 20%, P=0.001; 1% vs 13%, P=0.001; 1%
vs 16%, P=0.001) and mean power (4% vs 21%, P=0.006; 3% vs 15%, P=0.004; 6% vs 11%,
P=0.049) compared to placebo. No sex differences were detected. Muscular endurance
increased mean and peak power post-training in all groups (P=0.001). Also, similar acute
caffeine effect was found pre- and post-training.
CONCLUSION:
Caffeine intake (3 mg/kg of body mass) before resistance exercise enhances 1RM and promotes
a higher mean and peak velocity at 25-50% in bench press and 25-75% in back squat exercise
after 8-weeks of training in both male and female participants. Therefore, prolonged pre-
exercise caffeine intake accelerates neuromuscular performance adaptations to resistance
exercise to a similar extent in male and female participants.