Long-held views that sex diminishes athletic prowess have been debunked by researchers at the University of Florence, Italy.

They did so by sifting through studies that made the claim and applying stringent criteria to filter the most reliable of the studies. Distilled down to a mere nine such studies, they collated their results. What they found was surprising.

Laura Stefani, assistant professor of sports medicine at the University of Florence and lead author of the review, summed up the analysis: "We show no robust scientific evidence to indicate that sexual activity has a negative effect upon athletic results." Their results were published in the journal Frontiers in Physiology.

One study, based on female athletes, found no difference in strength if they had sex the night before. Another actually showed a beneficial effect on the performance of marathon runners. While the studies did provide some insight, Dr. Stefani and her colleagues were surprised about the lack of reliable research on the topic. "We clearly show that this topic has not been well investigated and only anecdotal stories have been reported," Stefani said. "In fact, unless it takes place less than two hours before, the evidence actually suggests sexual activity may have a beneficial effect on sports performance."

The review also revealed that males were more frequently studied than females, with no comparison of effects across genders. In addition, cultural differences toward sexual activity may influence how much or how little impact it may have.

The researchers noted other important oversights. "No particular importance has been laid on the psychological or physical effects of sexual activity on sports performance, or upon the different kinds of sports," Stefani said. 

Stefani and her team point out the need for comprehensive investigation into the topic — and in an arena where wins are measured in microseconds and centimeters, anything that could impact results is crucial.

But for now, the authors conclude, since long-held abstinence theories appear to be unfounded, athletes should not feel guilty when engaging in sexual activity up to the day before competitions.