Resumen de Effects of Caffeine Chewing Gum on Exercise Tolerance and Neuromuscular Responses in Well-Trained Runners
Naiandra Dittrich, Marilia C. Serpa, Elisa Cristina Lemos, Ricardo Dantas de Lucas, Luiz Guilhermo Antonacci Guglielmo
This study aimed to investigate the effects of caffeinated chewing gum on endurance exercise, neuromuscular properties, and rate of perceived exertion on exercise tolerance. Twelve trained male runners (31.3 +/- 6.4 years; 70.5 +/- 6.6 kg; 175.2 +/- 6.2 cm; 9.4 +/- 2.7% body fat; and V[Combining Dot Above]O2max = 62.0 +/- 4.2 ml[middle dot]kg-1[middle dot]min-1) took part of the study. The athletes performed an intermittent treadmill test to determine maximal aerobic speed and delta 50% ([DELTA]50%) intensity. In the following visits, they performed 2 randomized time to exhaustion tests (15.4 +/- 0.7 km[middle dot]h-1) after the ingestion of 300 mg of caffeine in a double-blind, crossover, randomized design. Maximal voluntary contraction of the knee extensor associated to surface electromyographic recording and the twitch interpolation technique were assessed before and immediately after the tests to quantify neuromuscular fatigue of the knee extensor muscles. Caffeine significantly improved exercise tolerance by 18% (p < 0.01). Neuromuscular responses decreased similarly after time to exhaustion in both exercise conditions; however, athletes were able to run a longer distance in the caffeine condition. The performance improvement induced by caffeine seems to have a neuromuscular contribution because athletes were able to run a longer distance with the same neuromuscular impairment.
