The increase of exercises\u2019 duration, and therefore the necessity of high muscle strength value maintenance during more time, could invite us to reconsider the importance of the aerobic training in men\u2019s artistic gymnastics (MAG). On the other hand the profile of the cardiac demand during competition has little to do with the one during training, besides the expected differences between adults (with more difficulties and a larger repertoire) and young gymnasts (with basic elements and a smaller repertoire). In this study the heart rate is monitored during 15 training sessions with 5 gymnasts of 9 years of age. In addition, to determine the cardiac demand (HR) during training, we want to verify if the heart rate (HR) is a useful register of the work load. The results demonstrated that HR, used in the same way as we register the competitive effort in adult elite gymnasts, is not convenient as an indicator of the training effort in young gymnasts. In spite of having organised the session by means of BM (methodological blocs with intentionally similar work contents), the cardiac affectation varies, not only between subjects, but also for a same subject in different days. It is possible that some estimation formulae of the external work load, based more on the content than on the cardiac demand, may be more appropriate to adjust the training load.<\/p>\n\n