Walter, A. A., Herda, T. J., Ryan, E. D., Costa, P. B., Hoge, K. M., Beck, T. W., Stout, J. R., & Cramer, J. T. (2009). Acute effects of a caffeine-containing thermogenic supplement on endurance performance and muscular strength in men. ACSM 56th Annual Meeting, Seattle, Washington. Presentation number 1902.

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This study determined the effects of a thermogenic nutritional supplement on muscular strength, endurance performance, and rating of perceived exertion during cycle ergometry in college-aged men (N = 20). Testing took place over a three-week period, with three laboratory visits separated by seven days. During visit 1, a graded exercise test was performed on a cycle ergometer until exhaustion (increase of 25 W every two minutes) to determine the maximum cycle ergometry power output (W) at the VO2peak. In addition, one-repetition maximum (1 RM) strength was assessed for the bench press and leg press exercises. During visits 2 and 3, Ss consumed a capsule containing either the active supplement (200 mg caffeine, 33.34 mg capsaicin, 5 mg bioperine, and 20 mg niacin) or a placebo (175 mg of calcium carbonate, 160 mg of microcrystalline cellulose, 5 mg of stearic acid, and 5 mg of magnesium stearate in an identical capsule) 30 minutes prior to the testing. Testing included a time-to-exhaustion ride on a cycle ergometer at 80% of the previously-determined power output at VO2peak followed by 1 RM leg press and bench press tests. Rating of perceived exertion was also assessed throughout the time-to-exhaustion tests.

There were no differences between the active and placebo trials for bench press, leg press, time-to-exhaustion, or rating of perceived exertion. However, for the bench and leg-press scores, the baseline values (visit 1) were less than the values recorded during visits 2 and 3.

Implication. An active supplement containing caffeine, capsaicin, bioperine, and niacin did not alter muscular strength, cycling endurance, or rating of perceived exertion during a time-to-exhaustion cycling ergometer trial.

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