Athletes often talk to themselves before a serve, a jump or a sprint, whether to stay calm or to push harder. Coaches have long encouraged the habit, but researchers have argued about when and how much it helps. An updated review of randomised trials suggests that self-talk does improve sports performance, and that what athletes say to themselves matters.

Researchers at Wuhan Sports University and Central China Normal University pooled the results of earlier trials in a meta-analysis. The findings appear in BMC Psychology. The team searched seven electronic databases and kept 33 studies that met their criteria.

Together the studies provided 56 effect sizes and 1,848 participants. The analysis used a three-level model, which allows for the fact that one study can report several results. The team checked the quality of each trial with a standard risk of bias tool and graded the strength of the evidence.

Self-talk is the words or phrases people say to themselves, aloud or silently, to guide attention, build confidence or control effort. A moderator is a factor that changes how strong an effect is. A meta-analysis combines many studies to give one overall estimate.

Self-talk improved sports performance overall, with a moderate effect that was statistically significant. The content of the self-talk was a significant moderator, which means some kinds of phrases worked better than others. This was the clearest sign of what separated stronger results from weaker ones.

Several other factors made no significant difference. These were the skill level of the athletes, how demanding the movement was, whether the self-talk was spoken aloud or silent, and whether it used first or second person. The situation in which self-talk was used and the length of the programme also did not matter, and nor did interactions between motor demand, content and overtness.

The review was designed to settle some earlier disagreements, partly by including newer trials than previous reviews. Its results suggest that the benefit does not depend on being an elite athlete, nor on saying the words out loud. That may make self-talk an easy tool for coaches and amateur players alike.

The study has clear limits. A test for publication bias pointed to a possible small-study effect, meaning that small trials with positive results may be over-represented, so the overall figure should be read with caution. The authors say that more high-quality studies are needed to test how each moderating factor shapes the effect.

Earlier reviews have also found that self-talk helps sport performance, and this update reaches the same broad conclusion with a larger pool of trials. It adds a more careful look at what shapes the effect, and it points to the wording of self-talk as the factor most worth studying.