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Camilla Astley, Diego Souza and Marcos Polito

Purpose:

To compare the acute effect of caffeine ingestion on performance in young judo athletes.

Method:

In a randomized double-blind design, eighteen judo athletes (16.1 ± 1.4 yrs.) were evaluated on three nonconsecutive days. On the first day, the special judo fitness test (SJFT) was used as a control session. On the second day, the sample was randomly divided into two equal groups. One group received 4 mg.kg-1 of caffeine (capsule) and the other group received a placebo. After resting for 60 min, the sample performed the SJFT. On the final day of testing, the same procedure was performed but the substance ingested was exchanged between the groups.

Results:

Heart rate (HR) and rating of perceived exertion (RPE) were recorded throughout the applications of the SJFTs. Caffeine ingestion did not induce changes in HR, but reduced the RPE compared with the placebo session (7.0 ± 1.1 vs 8.2 ± 2.0; p < .05), increased the number of throws applied (29.0 ± 2.6 vs 22.1 ± 3.4; p < .01) and reduced the SJFT index (12.2 ± 0.5 vs. 15.7 ± 0.9; p < .001).

Conclusion:

4 mg.kg-1 did not alter HR but improved performance on SJFT in young judo athletes and reduced the RPE.

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Diego B. Souza, Michael Duncan and Marcos D. Polito

Purpose: To examine the effects of acute caffeine (CAF) intake on physical performance in 3 sets of unilateral knee extensions with blood-flow restriction. Methods: In a double-blind crossover design, 22 trained men ingested 6 mg·kg−1 of CAF or a placebo (PLA), 1 h prior to performing unilateral knee-extension exercise with blood-flow restriction until exhaustion (30% of 1 maximal repetition). Results: There was a significant difference in the number of repetitions between the CAF and PLA conditions in the first set (28.3 [5.3] vs 23.7 [3.2]; P = .005), second set (11.6 [3.1] vs 8.9 [2.9]; P = .03), and total repetitions performed across the 3 sets (44.5 [9.4] vs 35.0 [6.6]; P = .001). Blood lactate was also significantly different (P = .03) after exercise between the CAF (7.8 [1.1] mmol·L−1) and PLA (6.0 [0.9] mmol·L−1). In regard to pain perception, there was a difference between the CAF and PLA in the second (6.9 [1.5] vs 8.4 [1.4]; P = .04) and third sets (8.7 [0.4] vs 9.5 [0.6]; P = .01). No differences were found for perceived effort. Conclusion: Acute caffeine intake increases performance and blood lactate concentration and reduces perception of pain in unilateral knee-extension exercise with blood-flow restriction.