Kruisselbrink, D., Rosendahl, B., Phillips, W. L., Strokan, K. E., & Murphy, R. J. (2005). Effects of caffeine and lorazepam on the performance of female soccer players. Medicine and Science in Sports and Exercise, 37(5), Supplement abstract 935.

Speed and accuracy of decision-making, strength, power, and endurance were tested on female varsity soccer players (N = 14) after ingesting caffeine (high-induced arousal, 5mg/kg), lorazepam (low-induced arousal, 1 mg), and 200 mg ascorbic acid as the placebo-control condition. Motor/perceptual performance was assessed as responses to 24 life-size video clips of soccer situations.

There were no differences between the three substances for resting heart rate, blood pressure, perceptions of somatic-anxiety and self-confidence, and movement initiation time. Response time was higher with lorazepam than the control, grip strength was higher for caffeine than in the other two conditions, a lorazepam impaired vertical jump when compared to the other two conditions.

Speed of decision-making was not altered noticeably by any condition but physical performance was affected by both caffeine and lorazepam.

Implication. Caffeine boosts performance without impairing perceptual capabilities.

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