CSP and RPQ results.

(A) Mean change and (B) individual data of the normalised CSP duration, depicted as a percentage change from the Pre Measures. These results show that CSP duration lengthened similarly in both groups, suggesting that corticospinal inhibition increased regardless of whether head impacts from football headings were experienced. (C) Mean change and (D) individual data of the (non-normalised) CSP duration, depicted as values in milliseconds. This confirms that the results in (A) and (B) are not a by-product of normalising the CSP duration. (E) Headaches and (F) Dizziness symptoms, as evaluated with the RPQ. The Headings group showed greater headaches and dizziness symptoms after headings were performed as compared to the Control group. This indicates that symptoms of head impacts were experienced in the Headings, but not in the Control group. For panels (A), (C), (E), and (F), the mean ± 95% CIs are shown. Asterisks (*) denote significant differences.