Participants
All 19 participants (age 22.5 (3.5) years; height 176.2 (6.5) cm; body mass 78.8 (13.2) kg; habitual caffeine intake: 62.55 (94.01) mg/day). A priori power analysis, using an expected effect size (f) of 0.55 for peak eccentric power on the Romanian deadlift test, an α of 0.05, a statistical power of 0.80All participants were interviewed verbally about their exercise habits over the previous 6 months. They were instructed to avoid caffeine-containing foods such as coffee, energy drinks, tea and chocolate for 24 h prior to the formal experiment. Excessive exercise training was prohibited for 72 h prior to the study. All potential problems that participants may encounter during the experiment were explained before the study began and the procedure was fully explained. Participants were asked to complete an informed consent form. This study was approved by the Institutional Review Board of Jen-Ai Hospital—Dali Branch (111-09) and registered in the ClinicalTrials.gov (Date: 22/02/2022; ID “NCT05900349”; 