Direct player observation is needed to accurately quantify heading frequency in youth soccer

In soccer, heading may be related to subsequent neurological impairment. Accurate measures of heading exposure are therefore important. This study evaluated whether 12 female youth players accurately recalled their average number of headers over an entire soccer season (20 games total). Their self-reported average number of headers per game was multiplied by the number of games that they participated in, and were compared to actual number of headers extracted from game video. All players overestimated the number of headers compared to game video. Linear regression analysis indicated that self-reported headers overestimated the number of headers by 51%. While self-reports are a convenient way to estimate heading behaviour, they do not accurately represent the number of headers that players perform. Self-reports of heading exposure should be interpreted with caution.