In order to obtain data about human head tolerance, the LPB-APR has conducted some experimentations with volunteer boxers. Five fights, i.e. fifteen rounds were carried out.Such research was undertaken because they expose themselves, in their normal body activities to direct head impacts.In an earlier publication, the methodology used for these experimentations was presented. The scope of this paper is to present the results obtained : the head accelerations. the head kinematics, the physiological effects.The findings showed that the angular accelerations were in all cases higher than 3500 rd/s2 exceeding the values considered as tolerance limit for volunteers given in the literature already available. The maximum angular velocity was 48 rd/s with a corresponding angular acceleration of 13600 rd/s2.In complement to physical measurements, tests of Event Related Potential Assessment of Attention and Orienting Reaction were performed by the CNRS-LENA in Hôpital de la Salpétrière, Paris.The data recorded were analysed in statistical way for ail boxers together. This sophisticated analysis did not indicate any anomaly in the results, except for one case where a small effect was observed, although the behaviour of the boxers remain in the normal range. This particular effect consists on an impairment of the ability to detect and react towards stimuli delivered in the right ear.