The research aims to determine: (1) the difference in influence between small side games and circuit training methods on improvementVO2max; (2) the difference in the influence of high and low Body Mass Index on improvementVO2max; and (3) interaction between training methodssmall side game andcircuit training and high and low body mass index to increaseVO2max.

The research method is an experiment with a 2x2 factorial design. The population in this study was 40 participants of the MTS Muallimin Futsal extracurricular, Yogyakarta City. The sample in this study was 20 people taken using techniquespurposive random sampling, then do itordinal pairing to divide each group. The research instruments used were meters and scales to measure body mass index, meanwhileVO2max usemultistage fitness test. Data analysis used tests for normality and homogeneity requirements, Two Way Anova test and Post Hoc test with Tukey.