Caffeine enhances jumping performance in elite volleyball players

As coaches, we have the responsibility of providing our athletes with the best opportunity to be successful on the field. We strive to optimize performance through training and nutritional interventions. In an athletes’ pursuit to constantly up their game, they will eventually be confronted with the option of using sport nutrition supplements. In this situation, the coach must consider (at least) 3 important questions concerning a given sport supplement product:

1. Is it legal?
2. Is it safe?
3. Is it effective?

Being able to answer these questions should help the coach guide the athlete to making the most informed decision possible. A review of the available research will ultimately show that very few sport nutrition supplements can substantially improve performance. However, caffeine is one of the supplements that tends have a decent track record of success and its supplementation may be worth exploring.

In a new study published ahead of print in the International Journal of Sports Physiology and Performance, the effects of moderate doses of caffeine ingestion on countermovement jump performance was investigated. A group of 10 elite male volleyball players volunteered for this study. In a randomized, cross-over design, the athletes performed two trials of countermovement jumps on a force plate separated by one week, with or without caffeine. This was a double-blind study, meaning that neither the researchers nor the athletes knew at which trial they were given caffeine in an effort control for bias and placebo effects. Three countermovement jumps were performed following 60-min of placebo or caffeine (5 mg/kg) ingestion. At 24 hours post-trial, all subjects completed questionnaires regarding any potential side effects that may have encountered from the caffeine.

The results showed that caffeine ingestion resulted in significant increases in numerous markers of performance during the countermovement jump including peak concentric force output (6.4%), peak power (16.2%) flight time (5.3%), peak velocity (12.6%) and peak acceleration (13.5%). In addition, caffeine ingestion reduced the time between peak power and peak force (16.7%). Diastolic blood pressure increased by an average of 13% from caffeine ingestion and no adverse side effects were noted from the questionnaires. This study adds to the growing body of evidence demonstrating that caffeine intake may enhance neuromuscular performance in athletes.
Reference: Zbinden-Foncea, H. et al. Effects of Caffeine on Countermovement Jump Performance Variables in Elite Male Volleyball Players. International Journal of Sports Physiology and Performance. In press.