Results of CFA consisting of the selected 9 items indicated a good fit to the data (e.g., AGFI=0.968, CFI=0.994, RMSEA=0.032, AIC=80.739) (Fig. 3). The causal structure model of the defending skills was also statistically valid (AGFI=0.966, CFI=0.991, RMSEA=0.037, AIC=83.061) (Fig. 4). These results indicated that SDSS was statistically valid for measuring defending skills in soccer, and that the defending skills of soccer were constructed from 3 sub-domains of “Delaying attack”, “Forcing play in one direction”, and “Squeezing working space of attackers”.