We verified the acute effect of ischemic preconditioning (IPC) in cyclists before high-intensity and short-duration activity. 15 amateur cyclists participated in a random crossover model on 2 different days [IPC or CONTROL (CON)]. Ischemic preconditioning consisted of 4 cycles of 5 min occlusion/5 min reperfusion in each thigh. After IPC or CON, volunteers performed a series of Wingate tests to evaluate anaerobic performance (maximal [Pmax] and medium [Pmed] power output, total anaerobic power, and fatigue index). Blood lactate concentrations were assessed at 6 min after each Wingate test. Ischemic preconditioning decreased Pmax (p<0.05), Pmed (p<0.01), and total anaerobic power (p<0.01) in the first Wingate, and decreased Pmed (p<0.01) and total anaerobic power (p<0.01) in the second Wingate (p<0.01). No significant differences were found in blood lactate or fatigue index between IPC and CON. In conclusion, our results indicate that IPC has a detrimental acute effect on anaerobic performance in amateur cyclists. Compared with positive results of previous studies, the effect of IPC seems to be dependent on the type of exercise.

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-The aims of the study were: 1) to analyze the exercise intensity in several phases (six phases of 15 min) of soccer matches; 2) to compare the match time spent above anaerobic threshold (AT) between different age groups (U-17 and U-20); and 3) to compare the match time spent above AT between players' positions (backs, midfielders, forwards and wingabcks). Forty-four male soccer players were analyzed. To express players' effort, the heart rate (HR) was continuously monitored in 29 official matches. Further, HR corresponding to the intensity at the onset of blood lactate accumulation (OBLA) was obtained in a field test. The highest exercise intensity during match was observed in the 15-30 min period of the first half (p< 0.05). Match time spent above AT was not different between players from U-17 and U-20. In the comparison among players' positions, wingbacks showed lower time above AT (p< 0.05) than players of other positions. The intensity of effort is higher in the 15 to 30 minutes of play (intermediate phase), probably because the players are more rested in the beginning and wearing out is progressive throughout the game. It is also noteworthy that the intensity of exercise (HR and time above AT) of wingbacks was lower, probably because they usually are required to run a larger number of sprints and need more time below the AT to recover.Key words: Anaerobic threshold; Exercise test; Heart rate; Soccer. (sub-17 e sub-20) Resumo -Os principais objetivos do presente estudo foram: 1) comparar a intensidade de exercício em diversas fases (seis fases de 15 min) de partidas de futebol; 2) comparar o tempo de partida acima do limiar anaeróbio (LAN) entre diferentes categorias

Exercise intensity monitoring has been essential for the control and planning of sports training. Thus, the aim of the present study was to assess the chronic physiological demand of soccer players during an annual soccer season using blood biomarkers. Ten professional soccer players (21.2 ± 3.7 years) participated in this study. Blood samples were collected on the day before beginning of preseason (C1); at the end of preseason and beginning of competitive calendar (C2); and at the end of the competitive calendar. Interleukin-6 (IL-6), cortisol, testosterone, testosterone/cortisol ratio, creatine kinase and alpha-actin were evaluated. Statistical analysis was performed by using ANOVA with repeated measures and the post-hoc Tukey's test. Significance level was set at P<0.05. The results showed significant differences in the following situations: testosterone -C1 higher than C2 and C3; cortisol -C3 higher than C2; testosterone/cortisol ratio -C2 higher than C1, and C3 lower than C1 and C2; creatine kinase -C2 and C3 higher than C1; alpha-actin -C3 higher than C1. IL-6 concentrations were not different between C1, C2 and C3. It could be concluded that an annual soccer season imposes high physiological demand for professional players, since relevant changes in blood biomarkers analyzed were observed.