objectives: to show the possibilities of ultrasonography in the early diagnosis of alterations in asymptomatic athletes′knee structures, and the predisposing endogenous factors related to sport "overuse" lesions and to introduce it as a methodological procedure in the medical control of training of high-performance cuban athletes. methods: a descriptive cross-sectional study was performed on asymptomatic 300 non-athlete persons and 100 cuban olympic athletes. a novel methodology of sonographic scanning for the knee was used including static and dynamic studies, according to the sportive specialty, to determine the normal patterns, to detect alterations in joint structures as well as to estimate the sonographic rab (stands for ricardo anillo′s acronym, main author). an alternative to determine the misalignment of the extensor mechanism was created. the statistical processing used summary measures to compare sonographic alteration ratios observed in the knees and also chi square test. percentiles were calculated using data from 600 knees from non-athlete people and all this information was processed through the spss statistical program. results: fifty seven subclinical alterations were detected in the knees of 100 studied athletes, distributed as follows: 30 with synovitis; 26 malalignment of the extensor mechanism, 15 distorsions in hoffa′s fat, 14 changes in meniscus echostructure, 11 alterations in ligament echostructure and 7 in articular cartilage. conclusions: preventive sonographic diagnosis proved to be an effective imaging method for the biomedical control of athletes training. statistically significant differences were found in athletes and non-athletes in terms of frequency of sonographic alterations in the knees, being the athletes more prone to it.