Acute effects of preconditioning activity and caffeine intake on sprinting, anaerobic capacity and fatigue index in football players: Gender comparison and individual responses

The aim of the study was to investigate the acute effects of pre-conditioning activity (CA) and caffeine on sprinting, anaerobic capacity and fatigue index in male and female football players. Sixteen football players, 8 male and 8 female, participated in the study. Participants were tested on 5 different days 48-72 hours apart. Participants were randomized equally into control (CON), placebo (PLA), caffeine (CAF), placebo + preconditioning activity (PLA+CA) and caffeine + preconditioning activity (CAF+CA) groups. Except for the control day, 3 mg/kg caffeine or placebo was given on the other days. The "Brunel Mood Scale" (BRMS) was administered before and 50 min after caffeine or placebo. In addition, the participants' Rating of perceived exertion (RPE) and heart rate (HR) were measured at different times. A 10 and 30 m sprint test was performed at 2., 4., 6., 8., 1.0 and 12. minutes on CON, CAF and PLA day. Then Wingate anaerobic power test was performed. On the day of CAF+CA and PLA+CA, plyometric CA was applied and the same tests were performed. For the main effect and interaction between the parameters, repeated measures multi-way analysis of variance (ANOVA) was used. Partial eta squared (ηp2) was calculated for effect size. Kruskal-Wallis Test was used for comparisons between the interventions for the BRMS, and Wilcoxon Signed Rank Test was used to compare the pre-test and post-test values of the interventions. The results were also evaluated at the individual level by calculating the "Smallest Real Difference" values. As a result, 10 and 30 m sprint performance did not differ significantly between the conditions (p>0.05). In the Wingate test, CAF increased peak power performance compared to CON (p<0.05). No significance was observed for HR and RPE (p>0.05). Placebo and caffeine did not affect mood between interventions (p>0.05), but placebo and caffeine increased fatigue in male and female (p<0.05) in pre-test and post-test values within the intervention. In individual results, in 10-30 m sprint, peak power, average power and fatigue index, the performance of some participants increased while the performance of some participants decreased. When the individual results are examined in detail, it is seen that the performance increase is more. Individual differences should be taken into account in the combination of CA and caffeine intake for acute performance enhancement in football players.