The objective of this study was to gather evidence supporting the accuracy of the 30-15 Intermittent Fitness Test (30-15IFT) for individualizing interval training of young intermittent sport players. In 59 young intermittent sport players (age, 16.26 2.3 years), we observed the relationships between the maximal running speed (MRS) reached at the end of the 30-15IFT (MRS30-15IFT) and physiologic...