Caffeine is one of the few legal performance-enhancing substances that actually works. Several studies have found improvements in vertical jump height, reaction time and endurance following caffeine consumption.
We can now add improved repeat sprint ability to the list as well. A new Irish study investigated the relationship between caffeine gum ingestion and repeated sprint performance in team sport athletes. The researchers found that caffeine can diminish the fatiguing effects of performing repeat sprints with incomplete rest periods, albeit with one important caveat (which we'll address in a minute).
In the study, 18 male university rugby, soccer and hockey players performed 10 40-meter sprints. Each sprint was performed at 30-second intervals, meaning that recovery time between efforts was 30 seconds minus the time taken to complete the previous sprint.
Prior to the test, all subjects were given chewing gum. One group ingested a placebo that contained no caffeine while the other absorbed caffeinated gum. On average, the caffeine dose in the gum was 2.5 mg/kg of an individual's body weight, meaning an athlete weighing 80 kilograms (approximately 176 pounds) would ingest around 200 mg of caffeine.
So what happened?
The researchers found that caffeine consumption delays fatigue on repeat sprint efforts. However, only athletes with a low level (< 40 mg/day) of habitual caffeine consumption witnessed this positive outcome. Those with moderate-to-high levels (> 130 mg/day) of habitual consumption did not.
How to Use This Information
These study findings confirm what coffee drinkers have known all along: You build up a tolerance to caffeine over time. This habituation effect can be overcome by elevating consumption levels above what you're used to or through withdrawal which restores sensitivity.
For maximal athletic benefits, stay away from daily caffeine ingestion in the long run. This ensures you'll get the desired sprint performance boost you're looking for when you do slurp down a cup of coffee or pop a caffeine gum pre-match or at halftime.
Bloms, LP et al. "The Effects of Caffeine on Vertical Jump Height and Execution in Collegiate Athletes." Journal of Strength and Conditioning Research. 2016 Jul; 30(7):1855-1861.
Santos, VG et al. "Caffeine reduces reaction time and improves performance in simulated-contest of taekwondo." Nutrients. 2014 Feb 10; 6(2):637-649.
Wiles, JD et al. "Effect of caffeinated coffee on running speed, respiratory factors, blood lactate and perceived exertion during 1500-m treadmill running." British Journal of Sports Medicine. 1992 Jun; 26(2):116-120.
Evans, M et al. "Acute Ingestion of Caffeinated Chewing Gum Improves Repeated Sprint Performance of Team Sport Athletes With Low Habitual Caffeine Consumption." International Journal of Sport Nutrition and Exercise Metabolism. 2018 May 1; 28(3):221-227.
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