Effects Of Caffeine And Lorazepam On The Performance Of Female Soccer Players

Abstract

Cue utilization theory posits that high arousal narrows attention. Individuals also tend to produce over learned responses at higher levels of arousal. In skilled sport performers, then, high arousal may benefit performance by allowing them to avoid being distracted and focusing their visual attention on areas they have learned are information rich. PURPOSE To examine the effect of high arousal (caffeine induced), low arousal (lorazepam induced), and placebo-control (ascorbic acid) on perceptual and physical performance in female university soccer players. METHODS Speed and accuracy of decision making, strength, power and endurance were tested in 14 athletes (20.1 ± 2.9 yrs) after ingesting 5 mg/kg caffeine (high arousal), 1 mg lorazepam (low), and 200mg ascorbic acid (placebo-control) in a randomized, double-blind design. The somatic-anxiety and self-confidence subscales of the Competitive State Anxiety Inventory-2 were used to examine the perceived impact of the three substances. To test perceptual performance, athletes assumed a ready position and moved in response to 24 life-size video clips of soccer passes to their right and left. Movement initiation time relative to ball contact, and response accuracy were recorded. Strength, power, and endurance were assessed through grip strength, vertical jump, and a run to exhaustion on a treadmill. Cardiovascular function was monitored through resting heart rate and blood pressure. RESULTS The three substances did not produce significant effects with respect to resting heart rate, blood pressure, perceptions of somatic-anxiety and self-confidence, or movement initiation time. However; response accuracy was higher with lorazepam than ascorbic acid (p<0.05), grip strength was greater with caffeine than lorazepam or ascorbic acid (p<0.05), vertical jump was impaired with lorazepam compared to caffeine and ascorbic acid (p<0.01), and the trend towards a longer duration run to exhaustion with caffeine approached statistical significance (p=0.055). CONCLUSIONS The higher levels of arousal produced by caffeine and lower levels of arousal produced by lorazepam did not noticeably affect the speed of decision making. However; ingestion of caffeine and lorazepam led to differences in physical performance indicating that athletes were differently affected by them. The use of caffeine to boost arousal may provide some physical benefits to athletes without compromising perceptual capabilities.