Table 2. Differences between win rates for Level 1 game elements observed over three periods. Level 1 1970-2000 (1) 2001-2015 (2) 2016-2021 (3) (1) vs. (2) (1) vs. (3) (2) vs. (3) χ2 P< Ccorr n=9300 n=5410 n=4984 h-Cohen p* h-Cohen p* h-Cohen p* 1. Serve 12.52% 9.63% 8.27% -.092 <.001 -.140 <.001 -.048 .015 372.9 .001 .154 2. Serve+Counterattack 19.88% 21.16% 20.47% .032 .062 .015 .407 -.017 .381 3. Return 16.20% 14.36% 15.13% -.051 .003 -.030 .093 .022 .271 4. Return+Counterattack 12.06% 14.71% 14.39% .078 <.001 .069 <.001 -.009 .636 5. Attack+Counterattack 17.14% 17.01% 16.35% -.004 .835 -.021 .231 -.018 .372 6. Block+Counterattack 9.87% 7.43% 7.54% -.087 <.001 -.083 <.001 .004 .826 7. Push+Counterattack 3.20% 4.64% 8.55% .074 <.001 .133 <.001 .159 <.001 8.Attack-against-chop+Counterattack 2.92% 4.71% 4.01% .094 <.001 .060 .001 -.034 .081 9. Chop+Counterattack 2.26% 3.18% 2.25% .057 .001 -.001 .967 -.058 .004 10. Other 3.94% 3.16% 3.05% -.042 .016 -.048 .007 -.006 .744 h-Cohen – the value of h Cohen indicator (effect size), p* - statistical significance at p<0.017, χ2 – the value of chi-square test, p – the significance of χ2 test, Ccorr - corrected contingency coefficient.