In order to investigate the effects of intensive training on cardiorespiratory response to maximal exercise in soccer players, graded excercise stress tests were carried out before and after the training, and the results were compared.

Fourteen male soccer players of a university team with the mean age and career of 19.9 and 7.8 years, respectively, underwent intensive training for approximately 20 weeks, 6 days a week and 4 hours a day, which included running of 2 km daily during the last 8-9 weeks. The symptom-limited maximal exercise test was done by Bruce protocol.

After the training. HR max showed no significant changes but Vo₂ max, O₂ pulse and AT were increased approximately 13%, 12% and 10%, respectively. At maximal exercise, the V_E/M² was also increased 18%, but V_E/MVV was significantly decreased owing to a marked increase in MVV. However, the rest of various ventilatory parameters showed no significant changes.

These data indicate that the intensive training of about 20 weeks duration can further improve the level of cardiorespiratory fitness in the soccer players who have been regularly trained and are already highly fit.