The first rule of soccer is pretty obvious: don’t use your hands. But soccer’s signature move, heading the ball, can cause a detectable impact on players’ brains. And according to a study published Tuesday in Radiology, female players are more sensitive to the impact than males.

The study authors found that female amateur soccer players who frequently head balls showed more white matter brain alterations than their male counterparts. The study included 49 women and 49 men, ages 18 to 50, and examined MRI imaging of players’ brains. Each female player was compared to a male player of a similar age and with other similar characteristics including frequency of heading exposure.

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