The acute effects of a caffeine containing supplement on anaerobic power and subjective measurements of fatigue in recreationally active males

Studies show mixed results for the effects of caffeine on performance, warranting further investigation. The purpose of this study was to examine the acute effects of a caffeine-containing supplement on anaerobic power and subjective measurements of fatigue during resisted sprinting on men. Fourteen recreationally active men (N = 14; [mean ± SD], age: 21.0 ± 0.7 years, height: 178.5 ± 5.1 cm, body mass: 77.3 ± 9.6 kg, and percent body fat: 12.6 ± 4.8%) participated in a double-blind, placebo-controlled, within-subject crossover design study. The first visit required each participant to complete 3 sets of practice sprints on a nonmotorized treadmill ranging from 10 to 20 seconds. During the second visit, participants completed 5 more practice sprints ranging from 15 to 25 seconds. During the third and fourth visits, participants ingested one serving of a caffeine-containing or placebo beverage (the opposite beverage was consumed during the fourth visit), rested for 20 minutes, and completed a dynamic warm-up before sprinting. Anaerobic power was assessed using a countermovement vertical jump and nonmotorized treadmill sprint test. Psychological variables were scored using a 5-point Likert scale. No significant (p <= 0.05) differences were observed between conditions for average (p = 0.22) or peak power (p = 0.43). Both conditions resulted in a significant increase in fatigue, although the increase was less for the caffeine condition (caffeine [INCREMENT] = 0.93 and placebo [INCREMENT] = 1.71). These findings indicated that the caffeine-containing supplement improved perceived measures of fatigue but not power indices assessed through vertical jump or nonmotorized treadmill sprinting. The consumption of a caffeine beverage may be beneficial for reducing perceived fatigue during acute anaerobic exercise, particularly when repeated sprints are used.