Acute Caffeine Intake and Velocity Metrics

The purpose of this study was to determine whether the acute ergogenic effects of caffeine differ according to the velocity metric used to assess strength performance against different relative loads. Thirteen resistance-trained men completed a triple-blind, randomized, placebo-controlled, crossover study. Participants ingested either caffeine (3 mg·kg-1) or a placebo 60 min before performing bench press and back squat exercises at 25%, 50%, 75%, and 90% of one-repetition maximum (1RM). Mean velocity (MV) and mean propulsive velocity (MPV) were simultaneously recorded using a linear position transducer

Inclusion Criteria: * Age between 18 and 35 years. * Body Mass Index (BMI) \< 25 kg/m². * Resistance-trained individuals (more than 6 months of structured training). * Healthy men and women without neurological, cardiometabolic, immunological, or physical conditions that prevent them from exercising. * Participants must be able to perform the tests described in the following section. Exclusion Criteria: * History of neuromuscular diseases, heart disease, or conditions that may affect liver or muscle metabolism. * Use of drugs, stimulants, or sports supplements that could interfere with the dietary supplement used in the study. * Sedentary habits (less than 150 minutes/week of moderate exercise). * Having undergone prolonged periods of physical inactivity in the 6 months prior to the study. * Engaging in strenuous exercise within 48 hours prior to the tests.• Failure to replicate the same food intake on both experimental days. * Consumption of caffeine or any other stimulant after 6 pm on the day before the tests, to avoid headaches, discomfort, or lethargy in regular caffeine consumers.