Why Do Olympic Swimmers Slap Themselves?

If you’re tuning into the swimming events at the 2024 Paris Olympics, you’ve probably noticed many swimmers’ habit of slapping themselves right before a race. Which body parts they target—legs, chest, arms, etc.—depends on the swimmer, as does the technique (i.e., with an open hand or closed fist).

One widely cited reason for the practice is to increase blood flow to those areas. You can see those effects with the naked eye: The swimmers often get red and splotchy from all that slapping. As Matt Barbini, USA Swimming’s director of performance, told TODAY in 2021, “they consider it part of their warm-up or activation, just making sure that there’s sort of maximal blood flow going to those parts of the body before you swim.” According to Athlete Approved, “the pectorals, shoulders, biceps, and triceps are important for their performance, so those muscles will often be the first slapped. Those are also the muscles that are most easily slapped.” Then they’ll move onto the legs.

But while warming up in general is important before intense exercise, there’s hardly a wealth of scientific evidence proving that slapping in particular gives you a physiological edge in the pool over swimmers who don’t slap—so it’s possible that its value is more mental than physical. The moments right before a race, when all the swimmers are lined up behind their blocks, can feel pretty tense. 

As Barbini explained, “having a procedure and a routine that you go through during that time is really helpful mentally so you’re not just standing there letting the nerves get to you […] you go up your left arm, you go up your right arm, go across your chest […] anything that sort of kills those in-between moments before the race starts, I think, helps keep athletes calm.”

Athlete Approved also suggests a different psychological reason swimmers might slap themselves—to intimidate their opponents.

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