The aim of this study was to evaluate body fat content (BF) of elite athletes obtained by two different field methods for body composition measurements and to compare it with body mass index (BMI) values. The research was conducted on 40 male athletes (20 runners and 20 handball players) and 30 non athletes. BF was calculated from the skinfold values (BFsft) and estimated using a hand-held impedance analyzer (BFbia%). Body mass index, waist to hip ratio (WHR) and waist to stature ratio (WSR) were calculated from adequate anthropometric values. Comparing the BF content between non athletes and two different sport groups, significant difference was found in all parameters between runners and non athletes (p < 0.05). Significant difference was found between BF values of runners and handball players (p < 0.05). Runners have had significantly lower BF, estimated by both methods. They also have had significantly lower WHR and WSR (p < 0.05). In the group of athletes and non athletes with BMI higher than 25 kg/m 2 , or lower than 20 kg/m 2 , comparing with others, no significant difference was found in BFsft and WHR. BMI is not a good predictor of BF, because it does not provide specific information about body fatness, but rather body heaviness. Bioimpedance and anthropometry methods could be used to monitor non obese subjects in clinical routine and population based studies. For BF estimation in athletes, we recommend anthropometry, rather than bioimpedance because of inter individual and inter sports variations in arms length and regional masculinity.

The chronic effects of physical activity on cognitive functions are scarcely documented. The aim of this experiment was to give inligth on the influence of single bouts of exercise at different intensities on the amplitude and latency of P300 component of cognitive potentials in the offense team of American football players. The subject sample consisted of 11 male athletes – members of the American football team “Dukes” Novi Sad, all engaged in the offense team. The control group was formed of 10 age matched students of the University of Novi Sad who were not engaged in any organized physical activity. In the present study the participants were engaged in single bouts of exercise on a cycle ergometer at different intensities. In American football players the amplitude of P300 wave after exercise intensity achieved at 75% HRmax (Fz 15.34±3.99 mV; Cz 19.00±6.26 mV) was statistically higher (p<0.05) than the amlitude at rest (Fz 11.08±4.65 mV; Cz 13.00±5.16 mV) and after exercise at 60% HRmax (Fz 11.87±4.39 mV; Cz 13.43±3.13 mV). There was a significant decrease in amplitude after exercise at 90% HRmax (Fz 11.96±4.48 mV; Cz 13.82±7.10 mV) to the levels of baseline values obtained at rest. In the control group the amplitude of P300 wave after exercise intensity achieved at 60% (Fz 11.02±4.99 mV; Cz 13.98±2.31 mV) and 75% HRmax (Fz 11.58±3.97 mV; Cz 14.64±1.94 mV) were statisticaly higher (p<0.05) than the amplitude of P300 at rest (Fz 7.99±2.95 mV; Cz 11.56±1.81 mV) and after 90% of maximal puls (Fz 8.76±3.05 mV; Cz 12.63±3.31 mV). There were no differences (p>0.05) between the amplitudes after 60% and 75% of HRmax, as well as between the values obtained at rest and after 90% of HRmax. Short duration exercise corresponding to 75% HRmax facilitated cognitive processing in the CNS in athletes, showing that strenuous exertion on the field improves cognitive capabilities in American football players.