Arousal is the level of activation and alertness experienced by a performer. For example, a judo player may feel highly aroused the moments before a bout and much less aroused an hour after the contest has ended.

The 'inverted U' theory

The 'inverted U' theory proposes that sporting performance improves as arousal levels increase but that there is a threshold point. Any increase in arousal beyond the threshold point will worsen performance.

Inverted U graph, showing performance quality at low, medium and high arousal levels. Performance is highest at the medium (optimal arousal) and poor at low arousal (boredom) and high arousal (panic).

At low arousal levels, performance quality is low. This is described as under-arousal or boredom and might be experienced by an elite tennis player playing a lowly ranked opponent.

At medium arousal levels, sporting performance peaks. This can be described as optimal arousal and might be experienced when a boxer gets themselves in the right 'zone' to perform at their best.

At high arousal levels, performance quality deteriorates. This can be described as panic and might explain why a football player performs very poorly when their team is losing 3-0.

Changes in arousal

Sometimes arousal levels need to be changed within the same performance. A fly-half in rugby needs higher arousal when making a big hit compared to when they take a penalty kick when calmness would be beneficial.