Response of protein S100B to playing American football, lifting weights, and treadmill running

Objective 
To determine if serum S100B increases similarly as a result of playing American football compared to exercise alone.

Methods 
Serum S100B was measured in division III collegiate football players before and after every home game during a single football season. Serum S100B was also measured before and after subjects walked on a treadmill for 30 minutes at a leisurely pace, ran on a treadmill while wearing and not wearing a football helmet at 6 mph for 8 minutes, and performed low, moderate, or high intensity resistance exercise.

Results 
Serum S100B increased significantly (p<0.05) when subjects played in a football game, ran on a treadmill, or performed moderate intensity resistance exercise. Pre‐game serum S100B did not accumulate throughout the football season in any of the players (p>0.05). The increase in serum S100B during football games was moderately and significantly correlated to both the number of hits (R2=0.407) and plays (R2=0.484) that each player experienced (p<0.001). Post‐game serum S100B was greater in football players who played more than 50 plays compared to those players who played less than 50 plays, subjects who exercised on a treadmill, or subjects performing resistance exercise (p<0.05).

Conclusion 
It is unclear if the higher S100B concentration in football players playing at least 50 plays was caused by exercise or hits. Therefore, if serum S100B is to be used as a biomarker of impacts, and possible brain injury in sport, exercise time and intensity should be taken into account as confounding variables.