FIG. 1.

Sustained increase in serum SNTF concentrations in professional ice hockey players after concussion, but not concussion-free training. SNTF levels were measured in serum during the preseason (n=45) or serially after an in-game concussion (n=28), or before and after a training game (n=17). The mean serum SNTF levels (±standard error of the mean) were elevated at 1, 12, 36, and 144 h postconcussion, compared with the mean preseason baseline concentration, and the increases at the latter three time points were statistically significant (two-tailed t-test; *p<0.03; **p<0.002). At the time of return to play (RTP) after a period of rest, SNTF levels returned to their preseason baseline. In contrast to the pronounced effects of concussion, SNTF was unchanged 1 or 12 h after concussion-free training (p≥0.87). SNTF, calpain-derived αII-spectrin N-terminal fragment.