When using the 38mm ball, the correlative coeffi- dent of them for men was 0. 898, and for women 0. 922. And when using the 40mm ball, it was 0. 881 for men, and 0. 898 for women.

• 在使用38 mm乒乓球的情况下，相关系数男子为0.；898，女子为0