Background: Caffeine is the most widely used consumed ergogenic aid in athletic populations. With the raise in athlete monitoring protocols, caffeine usage may provide cause misinterpretation of monitoring data. Thus, the purpose of this investigation was to examine the potential impact of an acute dose of caffeine on vertical jump and isometric squat performance.
Methods: A single-blinded randomized crossover design of 12 (6 male and 6 female) recreationally trained participants was used. Each participant was given either a 400 mg dose of caffeine anhydrous or placebo condition 30 minutes prior to performing three trials of an isometric squat, countermovement vertical jump (CMJ), and squat jump (SJ) testing using a force platform. Mean values of the three trials were statistical compared between conditions using paired sample t-test for each variable of interest.
Results: Caffeine significantly increased peak force during the isometric squat (P=0.024). In the CMJ caffeine increased jump height (P=0.3), peak power (P=0.03), RSIm (P=0.001) and time to peak force (P=0.04). SJ mean force (P=0.04) and RSI (P=0.04) showed significant increases after caffeine consumption.
Conclusions: This data suggests that caffeine affects the CMJ to a greater extent than the SJ. Furthermore, the variables that appear to be impacted during the CMJ, are those used commonly in protocols to assess the fatigue or readiness of athletes. Thus, the consumption of caffeine prior to monitoring protocols may negatively influence the interpretation of results and the subsequent prescription of training.