Association between aerobic performance and physiological responses in Yo-Yo intermittent recovery test level 2, and the futsal-specific intermittent endurance test in trained futsal players

Objectives: This prospective cross-sectional study aimed to delineate associations between the performance and physiological responses to the Bruce test with two field tests, the futsal intermittent endurance test (FIET) and the Yo-Yo intermittent recovery test level-2 (YYIR2) in elite male futsal players, in order to endorse one of field test to futsal coaches. Methods: Fifteen elite futsal players (age 20 ± 3 years) have been participated in this study. Main outcome measurements included aerobic power, heart rate, blood lactate, ventilation, VO2, VCO2, VE-VO2, and VE-VCO2 indicators during FIET, YYIR2, and the Bruce test with carrying out a portable gas analyzer. Results: The Bruce test is significantly correlated with FIET and YYIR2 with respect to key outcome measures, including performance (r>0.59), aerobic power (r>0.69), heart rate (r>0.80), and blood lactate levels (r>0.60). The two field tests, FIET and YYIR2, were found to exhibit strong to perfect interrelationships. When examining the indicators such as VE, VO2, VCO2, VE-VO2, and VE-VCO2, moderate to strong correlations were identified across all three testing methods. However, the relationship between the Bruce test and YYIR2 was particularly noteworthy in terms of respiratory exchange ratio (RER) and metabolic equivalent of task (METS), showing a significant correlation. Conclusions: The YYIR2 and FIET appear to be valid practical field tests for measuring aerobic fitness and performance in competitive male futsal players.