Comparing the 30–15 intermittent fitness test and treadmill test on VO2 max in elite female footballers

Abstract

Purpose. The study compared the 30–15 intermittent fitness test (30–15 IFT) and the treadmill-based multistage incremental test to evaluate their effectiveness in assessing cardiorespiratory fitness in elite female football players. Methods. Fifteen Slovenian National A Team female football players (age = 24.4 ± 5.7 years; height = 166.5 ± 6.2 cm; weight = 59.9 ± 6.0 kg) completed the 30–15 IFT and treadmill tests on separate occasions. Maximal running speed (MRS), maximal oxygen consumption ( O2 max), and maximum heart rate (HRmax) were measured, with Pearson’s correlation coefficients used to assess their relationships. Results. A moderate positive correlation was found between mean MRS treadmill speed (MRS_Treadmill) and O2 max from the 30–15 IFT (r = 0.533, p = 0.041). The O2 max from the 30–15 IFT and treadmill test showed a strong correlation (r = 0.756, p = 0.002), while the correlation between treadmill O2 max and mean MRS 30–15 IFT speed (MRS_30–15 IFT) was nearly perfect (r = 0.977, p = 0.000). The intraclass correlation coefficient (ICC) for single O2 max measurements was 0.689 [95% confidence interval (CI) = 0.271–0.888, p = 0.002], indicating moderate agreement, and 0.816 (95% CI: = 0.426 – 0.941, p = 0.002) for average measurements, indicating strong agreement. Conclusions. These results are important for coaches of elite women’s football. The reduced variability suggests that cardi-orespiratory fitness measures are more consistent in elite athletes than in diverse sports populations. This study’s unique contribution lies in its focus on elite national female football players, providing specific findings that enhance the utility of the 30–15 IFT in this specialised context.