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, 16.2 +/- 2.3 years), we observed the relationships between the maximal running speed (MRS) reached at the end of the 30-15IFT (MRS30-15IFT) and physiological variables elicited by shuttle intermittent runs, including maximal oxygen uptake, explosive power of lower limbs, and the ability to repeat intense exercise bouts through cardiorespiratory recovery kinetics during exercise. To observe the capacity of the 30-15IFT to prescribe suitable running intensities for interval training sessions, we compared heart rates (HRs) reached during 3 series of intermittent runs, where distances were set according to the MRS30-15IFT and to MRS reached with 2 popular continuous field tests: the University of Montreal track test and the 20-m shuttle run test. The results show that the MRS30-15IFT is significantly correlated with all physiological variables elicited by shuttle intermittent runs (P < 0.05). Although mean HR were not different among the 3 series of intermittent runs, HR recorded during the runs based on MRS30-15IFT presented significantly less interindividual variation than when the continuously determined MRS were used as reference speeds. In conclusion, we can say that the 30-15IFT leads to an MRS that simultaneously takes into account various physiological qualities elicited when performing shuttle intermittent runs. For scheduling interval training sessions, the MRS30-15IFT appears to be an accurate reference speed for getting players with different physiological profiles to a similar level of cardiorespiratory demand and thus for standardizing training content.

Cardiorespiratory and cardiac autonomic responses to 30-15 intermittent fitness test in team sport players.

The aim of the present study was to a) examine the relationship between performance of the Yo-Yo Intermittent Recovery Test Level 1 (Yo-YoIR1) and the 30-15 Intermittent Fitness Test (30-15IFT) and b) compare the sensitivity of both tests to training. Fourteen young soccer players performed both tests before and after an eight-week training intervention, which included six sessions/week: two resistance training sessions, two high-intensity interval training sessions after technical training (four sets of 3:30 min of generic running and small sided games (4v4) during the first and second four-week periods, respectively, [90-95% maximal HR], interspersed with 3 min at 60-70% maximal HR) and two tactical-only training sessions. There was a large correlation between 30-15IFT and Yo-YoIR1 (r = 0.75, 90% confidence limits, CL 0.57;0.86). While within-test % changes suggested a greater sensitivity to training for the Yo-YoIR1 (+35%, 90%CL 24;45) compared with the 30-15IFT (+7%; 4;10), these changes were similarly rated as ‘almost certain’ (with chances for greater/similar/lower values after training of 100/0/0 for both tests) and moderate, i.e., standardized difference, ES = +1.2 90%CL (0.9;1.5) for Yo-YoIR1 and ES = +1.1 (0.7;1.5) for 30-15IFT. The difference in the change between both tests was clearly trivial (0/100/0, ES = -0.1, 90%CL -0.1;-0.1). Both tests might evaluate slightly different physical capacities, but their sensitivity to training is almost certainly similar. These results also highlight the importance of using standardized differences instead of % changes in performance to assess the actual training effect of an intervention.