In order to evaluate the to potential hazards related to athletic functional overload on the intervertebral disk we studied with MRI the incidence of intervertebral disk abnormalities in a group of 45 volunteers who had been playing professional volleyball for 3-7 years. As a control group we examined with MRI 30 professional swimmers as well. Among the volley-ball players the incidence of intervertebral disk alterations was 44.4%; they were represented by 8 cases of disk degeneration, 11 cases of bulging and 9 disk herniations (in 8 patients the simultaneous presence of more than one lesion was observed). In the control group the incidence of such lesions was 20%. The obtained results were correlated with the clinical findings and the age of the athletes. Among the 26 athletes with back pain only 13 had positive findings at MRI, while among the 19 asymptomatic athletes 7 showed lesions detectable with MRI. As for age, we observed that the younger athletes (17-19 years) had positive MRI findings in 38.5% of cases, while the players in the age group ranging from 23 to 26 years, had positive MRI findings in 56.2% of cases. The analysis of the different types of training of the volley-ball players and the control group, showed that 19 volley-ball players who followed appropriate training procedures had positive MRI findings in 21.1% of cases (in the control group the percentage was 20%). Among the 26 athletes who were trained with exercises that caused significant functional overload, 16 had intervertebral disk lesions at MRI (61.5%). Moreover, our data showed that the correlation of the incidence of disk lesions with the type of training (and relative varying degree of overload) is definitely more important than the one existing with the age of volley-ball players and the overall period of their athletic activity. MRI proved to be a useful technique for the early assessment of the intervertebral disk damage caused by an incorrect training in young athletes, even when asymptomatic.